NIST
Analytical Chemistry Division (9)
Stephen A. Wise, Chief
100 Bureau Drive, Stop 8390, Gaithersburg, MD 20899-8390
National Institute of Standards and Technology
Chemical Science and Technology Laboratory
Analytical Chemistry Division
FY04
Division Overview
I. Introduction
The Analytical Chemistry Division is one of five Divisions in the Chemical
Science and Technology Laboratory, National Institute of Standards and
Technology. The Division has approximately 100 scientists, technicians,
and administrative/clerical support staff and an annual budget of about
$18M of which about $8M supports programs for other Federal and State
Government Agencies and/or American industry on a cost reimbursable
basis.
The Division serves as the Nation's reference laboratory for chemical
compositional measurements and standards to enhance U.S. industry's
productivity and competitiveness, assure equity in trade, and provide
quality assurance for chemical measurements used for assessing and improving
public health, safety, and the environment. The Division maintains world-class
metrologically based core competencies in:
- Analytical Mass Spectrometry
- Analytical Separation Science
- Atomic and Molecular Spectroscopy
- Classical and Electroanalytical Methods
- Gas Metrology
- Nuclear Analytical Methods
- Microanalytical Technologies
These core competencies reside in five Groups [Spectrochemical Methods;
Organic Analytical Methods; Gas Metrology and Classical Methods; Molecular
Spectrometry and Microfluidic Methods; Nuclear Analytical Methods] and
provide the capability to carry out the Division's broad mission and
the flexibility to respond to changing and evolving national priorities.
The skills and knowledge derived from laboratory-based research concerning
the phenomena that underpin the measurement of a wide variety of chemical
species in a broad spectrum of matrices are applied to the development
and critical evaluation of measurement methods of known accuracy and
uncertainty. These internationally-recognized reference methods are
benchmarked against those maintained by other National Metrology Institutes
worldwide and are used to the deliver measurement services to the chemical
measurements community through:
- Critically evaluated Reference Measurement Methods and Procedures;
- Standard Reference Materials (SRMs);
- NIST Traceable Reference Materials (NTRMs);
- Measurement Quality Assurance Programs.
II. Division Project Areas in Support of Chemical Science and Technology
Laboratory Programs
Reference Methods and Standards for Clinical
Diagnostics
The objective of this project is to develop and maintain the measurements
and standards infrastructure to facilitate accurate decision-making
regarding the diagnosis, treatment, and prevention of diseases. Measurements
are responsible for 10% - 15% of the $1.7 T annual costs of healthcare
in the United States. A significant portion (25% - 30%) of health-related
measurements is performed for non-diagnostic reasons (re-tests, error
prevention and detection). Even modest improvements in measurement accuracy
and quality assurance will result in multi-billion dollar savings in
healthcare costs. Project drivers are therefore, measurement reliability
as it impacts healthcare costs and medical decision-making, regulatory
requirements, and international trade and competitiveness-related issues.
Project components include [1] Reference Methods for selected health
status markers (electrolytes, small organic markers, toxic and/or speciated
metals, protein-based markers) [2] Standard Reference Materials (pure
primary chemical standards, optical filter standards for instrument
calibration/assessment, body fluid-based materials), [3] interactive
measurement quality assessment activities, [4] strategic international
comparison exercises
NIST works with other government agencies (e.g., CDC, NCI, NIH), professional
organizations (e.g., AACC, CAP, NCCLS), the private sector (e.g., AdvaMED,
Mayo Clinic) and the international community through the recently formed
Joint Committee on Traceability in Laboratory Medicine to prioritize
measurement and standards needs.
Measurement Methods and Standards for Forensics
and Homeland Security
Forensic chemical analyses have become important tools for solving crimes
and assuring justice. Today, most forensic analysis techniques are qualitative
and are used to identify or confirm the presence or absence of certain
materials. However, in many cases, applying quantitative analytical
techniques can provide important additional information about material
sources or the significance of material identifications.
Project activities address measurement method and standards issues
related to alcohol and drugs of abuse testing, crime scene investigations
(gunshot and explosive residues, teleforensics), and chemical and biological
weapons detection.
Project priorities are driven by input from the U.S. Departments of
Justice and Homeland Security.
Measurement Methods and Standards for Nutrients,
Contaminants, and Adulterants in Foods
The integrity of the nation's food supply is important for public health
and safety. The development of reference methods and standards for nutrients,
contaminants, and adulterants in foods is essential in this regard.
Project components include measurement and standards issues related
to nutrients in food products, contaminants and adulterants in food
products, chemical composition and contaminants in herbal supplements/
nutraceuticals, and detection of genetic modifications in food products.
Project priorities are determined in consultation with the AOAC, FDA,
NIH, and the National Food Processors Association.
Environmental Measurements and Standards
Responsible stewardship of the environment is facilitated when measurements
of known accuracy are used in monitoring and decision-making. Activities
in this project involve the development of reference methods, the development
of Standard Reference Materials, and the provision of other measurement
quality assurance services to address measurement problems associated
with Drinking Water Quality, wastewater Chlorination/Dechlorination
Mechanisms, Atmospheric Monitoring and Global Climate Change Assessment,
Automotive Exhaust Emissions, Atmospheric Particulate Characterization,
Contaminants in Sediments and Soils, Contaminants in Biological Fluids
and Tissues, and Specimen Banking Technology.
Activities in this area support directly and indirectly federal agencies
such as, EPA, NOAA, DOE, DOD that have stewardship responsibility for
the environment; state laboratories, and the large, environmental testing
service sector that consists of private laboratories; secondary standards
producers; and proficiency testing organizations. Our environmental
projects also support industries and their consortia (e.g., AIGER, EPRI,
etc.) that require high quality and/or traceable measurements to respond
in a cost-effective manner to changing regulatory mandates concerning
emissions and waste disposal. Other activities support basic studies
and models that track the fate of pollutants over both time and space
and their impact on quality of life.
Methods and Standards for Advanced Materials
Characterization
Industrial and academic materials scientists often require accurate
information regarding the chemical properties of advanced materials.
These properties include chemical purity, trace element content, and
the distribution of elements within the material. Such information not
only allows optimization and control of production processes, but also
facilitates a theoretic understanding of both chemical processes and
material properties. As the Nation's reference laboratory for chemical
measurements, CSTL must not only provide the fundamental basis of the
nation's chemical measurement system, but also extend these capabilities
to the real world. The Analytical Chemistry Division does this by providing
direct measurements for customers and collaborators, by providing Standard
Reference Materials for instrument calibration and for measurement quality
assurance, and by making the latest measurement techniques and data
available to the advanced materials community.
The Division has a broad array of analytical measurement tools including
unique capabilities such as neutron activation analysis, prompt gamma
activation analysis, and neutron depth profiling to provide analytical
data and reference measurements needed to provide answers to important
measurement problems.
Methods and Standards for Commodities Characterization
The provision of accurate, accepted chemical characterization determinations
is critical for those materials whose commercial value, properties,
or suitability for use depend on their chemical composition. These characterizations
may require measurement of major component(s), identification and quantification
of contaminants, and/or determination of the spatial distribution of
components. This project requires ongoing identification of those commodity
areas with critical needs that can be addressed by NIST and strategic
selection of project tasks from among these.
Current project activities focus on sulfur in diesel fuels, composition
of metals/metal alloys (e.g., low carbon silicon steel, phosphorized
copper), a series of cement SRMs, and an electronic scrap artifact material
- the first of a new class of SRMs addressing industrial "green
product" goals in which key decisions, with significant economic
and ecological consequences, depend on the quality of analytical characterizations
of materials to be recycled.
Microanalytical Technologies - Lab on a Chip
This project focuses on facilitating the design and development of plastic
microfluidic systems by developing techniques to achieve greater control
of microflow and microchemistries performed in plastic microchannels.
In both the analytical and biotech industries, there has been tremendous
interest in recent years in the development of chip-based technologies
incorporating microfluidics. It is predicted that miniaturization of
chemical processes using these technologies will have a huge impact
on rapid point-of-care screening as well as high throughput screening.
For these devices to become commercially viable, the chemistries performed
in microfluidic systems must be well-controlled to provide accurate
and reliable results. In response to this need, the goal of our multi-year
program is to develop novel methods to evaluate and control chemistries
in microscale systems. First, we have developed methods to understand
and manipulate microflow in a predictable manne, since a lack of flow
control can lead to misinterpretation of analytical results. We will
also develop methods to accurately evaluate and control temperature
profiles in microchannels, since temperature is a critical parameter
that has a profound effect on reaction kinetics. Finally, we will develop
methods to fabricate and integrate components that allow for finer control
of chemical reactions including passive micromixers and microarrays.
Based on input from a young microfluidics industry, the fundamental
control of chemical reactions performed in microchannels is the underpinning
of a program designed to promote the commercial realization of plastic
microfluidic measurement systems.
Further discussions regarding the Division's core competencies, focused
project areas, and products/services delivered to customers are provided
in the Group Sections of this Overview and the Selected Technical Activity
Reports.
III. SRMs: Tools for Providing Chemical Measurement Traceability
Increased requirements for quality systems documentation for trade
and effective decision-making regarding the health and safety of the
U.S. population have increased the need for demonstrating "traceability-to-NIST"
and establishing a more formal means for documenting measurement comparability
with standards laboratories of other nations and/or regions. Standard
Reference Materials (SRMs) are certified reference materials (CRMs)
issued under the National Institute of Standards and Technology trademark
that are well-characterized using state-of-the-art measurement methods
and/or technologies for chemical composition and/or physical properties.
Traditionally, SRMs have been the primary tools that NIST provides to
the user community for achieving chemical measurement quality assurance
and traceability to national standards. Currently, NIST catalogs nearly
1400 SRMs; in FY04 NIST sold approximately 30,400 SRM units to more
than 6,500 unique customers. Approximately 24,500 of the units sold
were from the ~1000 different types of materials that are certified
for or support measurements of chemical composition.
During the past year, measurements were made to support our value assignments
for ~100 different SRMs. Thirty-eight new SRMs were completed in FY04
and another forty-eight SRMs were issued as renewals. Measurements were
made to confirm stability and/or update certificates on an additional
twenty SRMs. In addition, 40 gas mixture SRMs in cylinders were recertified
for 11 different Specialty Gas Companies and approximately 220 sets
of optical filter standards were re-value assigned for wavelength and/or
absorbance in the UV and NIR spectral region for more than 130 different
companies. Three new NIST Standard Reference Photometers were delivered
(one to U.S. EPA and two to other NMIs) and four recertified during
the past year. The following narrative descriptions of several new SRMs
completed during the past year illustrate the diversity of the industries
and societal segments impacted by the SRM services delivered by the
Division:
· SRMs for Dietary Supplements: More
than 50% of the U.S. population uses dietary supplements, accounting
for roughly $10 billion in sales every year. Standards are being developed
to address needs expressed by the Food and Drug Administration (FDA)
and the National Institutes of Health's Office of Dietary Supplements
(NIH-ODS) for reference methods and reference materials for dietary
supplements to provide quality assurance of analytical measurements
associated with the manufacturing process, verification of manufacturers'
label claims, and public health and safety concerns. Suites of SRMs
have been completed for Ephedra (SRMs 3240 - 3245) and Ginkgo biloba
(SRM 3246-3248). The Epdedra suite of SRMs consists of the authentic
plant, plant extract and mimics of commercial finished products. They
all have certified values for ephedrine alkaloids and several toxic
metals. The Ginkgo biloba suite of three SRMs consists of Ginkgo biloba
leaf, Ginkgo biloba extract, and Ginkgo biloba-containing tablets and
are certified for prepared ginkgolides, flavnoids, and toxic metals.
SRMs for multivitamin/multielement supplements, saw palmetto, bitterorange,
and St. John's wort will be completed in FY05-FY06.
· SRMs for Clinical Diagnostics: Homocysteine
is an amino acid whose elevated levels in blood correspond with increased
risk for heart disease and stroke, as well as other conditions such
as dementia. Folic acid is a vitamin that is known to reduce the risk
of neural tube defects in newborns. In addition elevated levels of forms
of folic acid (folates) in blood appear to reduce homocysteine levels.
NIST worked closely with CDC to develop a three level, frozen human
serum SRM (SRM 1955) for these two analytes. Value assignment involves
use of higher order reference measurement procedures involving isotope
dilution coupled with liquid chromatography-tandem mass spectrometry
(LC/MS/MS) performed at both NIST and CDC. This is the first serum-based
certified reference material for these two analytes
More than one million Americans will suffer a myocardial infarction,
or heart attack, this year. The presence of troponin I (cTnI). In the
blood is strong evidence that damage to heart tissue has occurred, and
the level of this protein in the blood is indicative of the severity
of the damage. Unfortunately, the different clinical assays used to
measure troponin I may give widely differing results - currently by
a factor of 30 -- complicating the diagnostic process. SRM 2921 is formulated
as a dilute solution of human cardiac troponin complex of the troponin
I, troponin C, and troponin T subunits, extracted from human heart tissue
under non-denaturing conditions. This SRM is certified for troponin-I
amount of substance content and has reference values for troponin-C
and troponin-T. Preliminary data indicate the proper use of this SRM
will decrease assay-to-assay measurement variability by a factor of
10.
· SRMs for Support of Blood and Breath
Alcohol Testing: Two new ethanol in water reference materials,
SRM 1828b and SRM 1847, with six and three concentration levels, respectively,
have been issued to replace the current SRM 1828a, which had only four
concentration levels. The concentration levels in SRM 1828b, Ethanol-Water
Solutions (Blood-Alcohol Testing: Six Levels), have been tailored to
correspond to legally relevant points, specifically, 0.02% and 0.04%
for "zero tolerance" and occupational alcohol testing, 0.08%
and 0.1% for state drunk driving laws, and 0.2% and 0.3% for an average
and high level for blood alcohol measurements. In addition, SRM 1847
has been developed to support Breath-Alcohol Testing. This SRM has three
concentration levels of ethanol in water (2%, 6%, and 25%) for calibrating
breath-alcohol instruments. The development of this expanded suite of
ethanol in water SRMs was supported in part by funding from Office of
Law Enforcement Standards in FY03 and FY04.
· New Sulfur in Fossil Fuel SRMs: SRM
2693, Sulfur and Mercury in Coal is the first bituminous coal SRM to
be issued with a certified value for sulfur of less than 1 %, and thus
fills an important industry need as requested by ASTM. Newer coal-fired
power plant are required to use coal containing less than 1% sulfur.
These plants generally need to blend coals of varying S content, and
need to be very confident that the blended compositions are below 1%
S. This new SRM will be used to assure the accuracy of measurements
made very near the regulatory limit.
The S concentration SRM 2770, Sulfur in Diesel Fuel, was designed to
help the petroleum industry meet the 15 ppm sulfur limit imposed by
the EPA for on-road diesel fuel that will go into effect in 2006. The
material was used as the test sample for the CCQM Key Comparison (K35)
for Low Sulfur in Diesel Fuel.
· SRMs for the Metals Industry: Silica
fume is a byproduct of producing silicon metal and ferrosilicon alloys,
and its chemical and physical properties make it a very reactive pozzolan.
No longer simply discarded, more and more silica fume is being recycled
through use in concrete instead of being placed in landfills. High-Performance
Concrete containing silica fume can have very high strength and durability.
Increasingly, state highway and transportation administrations require
high-performance concrete in bridges and roadways. Standard Reference
Material 2696 Silica Fume, is the culmination of a five-year development
project carried out by the Silica Fume Association and NIST with support
from the Federal Highway Administration. SRM 2696 is primarily intended
for use in evaluating chemical and instrumental methods of analysis
of silica fume used in conjunction with product specifications. Certified
values have been established for silicon expressed as SiO2 and six other
chemical constituents, plus reference values for five chemical constituents
and the physical measurement parameter Specific Surface Area determined
using nitrogen absorption. The SRM was issued in May 2004.
· Galvalume® is a hot-dip coating
applied to sheet steel to protect it from the elements. As the molten
alloy is used, it picks up Fe and Si from the sheet steel passing through
the pot. At elevated levels, Fe and Si have a deleterious effect on
the Galvalume® coating. Therefore, the pot must be analyzed frequently
and recharged at the appropriate time. ASTM International Committee
E01 requested that NIST develop SRM 2426, Galvalume® to support
the US steel industry. The material was prepared and donated by industry
laboratories. Homogeneity testing and quantitative measurements by XRF
were completed in FY04. Collaborative testing by industry laboratories
is expected to be completed in the fall of 2004 and we expect to issue
the SRM in FY05.
Additional examples are provided in the Group Overviews and Technical
Activity Reports that follow.
In order to address questions from the international community concerning
the quality of data provided on SRM certificates, NIST 260-136 "Definitions
of Terms and Modes Used at NIST for Value-Assignment of Reference Materials
for Chemical Measurements" was published in January 2000. NIST
SP 1012: "An Approach to the Metrologically Sound Traceable Assessment
of the Chemical Purity of Organic Reference Materials" was developed
and published. In addition, the Division's Quality Manual that summarizes
and formalizes the Division's policies and approaches to addressing
quality-related issues concerning the services that we provide has been
updated to assure appropriate compliance with ISO/EC 17025 and ISO Guide
34.
IV. NTRM Programs for Leveraging NIST Resources and Efforts
As it has the world's leading, most mature, and most comprehensive
reference materials program, most of the world looks to NIST as the
de facto source for high quality CRMs to support chemical measurements.
NIST has met the reference materials needs of U.S. industry and commerce
for nearly 100 years. While our reference materials program has focused
primarily on U.S. requirements, it is clear that these materials address
international measurement needs as well. As demonstration of quality
and "traceability" for chemical measurements have become increasingly
global issues, the need for internationally recognized and accepted
CRMs has increased correspondingly. Their use is now often mandated
in measurement/quality protocols for analytical testing laboratories.
Coupled with the fast pace of technological change and greater measurement
needs, the demand for additional quantities and additional specific
varieties of reference materials has mushroomed. NIST, by itself, does
not have the resources to provide SRMs (exact sample types, unique compound
combinations, concentrations, etc.) to meet all these needs. Without
a significant shift in paradigm, we will not to be able to address future
needs for reference materials; neither nationally nor internationally.
The NIST Traceable Reference Materials (NTRM) program was created to
partially address this problem of increasing needs for reference materials
with a well-defined linkage to national standards. An NTRM is a commercially
produced reference material with a well-defined traceability linkage
to existing NIST standards for chemical measurements. This traceability
linkage is established via criteria and protocols defined by NIST and
tailored to meet the needs of the metrological community to be served.
The NTRM concept was implemented initially in the gas standards area
to allow NIST to respond to increasing demands for high quality reference
materials needed to implement the "Emissions Trading" provisions
of the Clean Air Act of 1990 (while facing the reality of constant human
and financial resources at NIST). The program has been highly successful.
Since its inception, 12 specialty gas companies (SGC) have worked with
NIST to certify over 9000 NTRM cylinders of gas mixtures that have been
used to produce more than 500,000 NIST-traceable gas standards. A recent
study conducted by RTI International estimates that the "net benefits"
of this NTRM program projected through 2007 will be between $50M and
$63M with a social rate of return of about 225%.
Operationally, in the Gas NTRM Program, a specialty gas company prepares
candidate gas mixtures in batches of ten or more cylinders, analyzes
these, and submits the data to NIST. NIST selects 10% of the cylinders
in the batch and analyzes them so that NIST can value-assign the batch.
The cylinders are returned to the SGC with Certification documentation
for the batch. The cylinders are under control of the SGC and can be
sold to end users to provide a NIST traceable gas or the NTRM mixtures
can be used by the SGC in the analysis of other mixtures that are then
sold to provide traceability. During FY04, 14 new gas NTRMs were certified
for three companies. These included two batches of very difficult 20
µmol/mol nitric oxide in nitrogen NTRMs. An additional twenty-nine
NTRM batches were recertified this year for 4 companies to extend their
certification period by 4 years.
During the past year, the NTRM program was expanded to include a newly
defined "NTRM prime" designation to meet additional needs
of the automobile industry. For NTRM prime batches NIST will individually
certified each cylinder to provide the lowest uncertainty possible.
Normal NTRM batches are batch certified using NIST and specialty gas
company data. In effect the new NTRM prime cylinders will become industry
sponsored SRM quality standards, which will better meet the need of
the AIGER companies. The NTRM prime program is ready now; NIST is waiting
on AIGER to initiate the first batch.
We had previously planned to develop NTRMs in the Elemental Standards
area. Those plans are being re-evaluated. Our single element spectrometric
solution standards program (SRM 3100 series) is now on its firmest footing
since its inception. All elements are now in stock and the uncertainty
model was updated to bring the certificates into full compliance with
the ISO Guide to Uncertainty of Measurements (GUM). This uncertainty
analysis includes incorporation of the new "Type B on Bias"
method developed by the NIST Statistical Engineering Division, as well
as a different treatment for transpiration correction. Improvements
in packaging instituted several years ago are now paying off with longer
shelf lives and larger lot sizes that have reduced the need for replacement
of expired or sold out SRMs. Three years ago, over 20 SRMs in the series
needed to be produced and certified over the course of a year. Over
the past two years, only three SRMs needed to be replaced. Emphasis
has shifted to stability testing of SRMs in stock, and working with
commercial standards producers to develop strong and defensible claims
of traceability between their CRM products and the SRM 3100 Series.
Toward that end, we have developed a method for the rigorous comparison
of single element solutions standards to the SRM 3100 Series that has
been published in Analytical Chemistry. The paper includes, as supplemental
information, a software tool to help laboratories outside NIST implement
the method to establish their claim of traceability to the SRM
We recognize that the NTRM model is only applicable in selected areas
where the science, metrology and economics are all favorable. In the
remaining areas, such as complex matrix standards, we have begun to
leverage our resources through increased strategic collaborations with
other National Metrology Institutes and selected U.S. laboratories.
Additional details are provided in Technical Activity Reports that follow
concerning our collaborative activities with both private sector U.S.
laboratories and providers of commercial reference materials and proficiency
testing services as well as other National Metrology Institutes worldwide.
V. Intrinsic Standards
Intrinsic standards "based on well characterized laws of physics,
fundamental constants of nature, or invariant properties of materials"
(ANSI/NCSL Z540) have many uses in physical and chemical metrology.
Such standards can reduce the need for (1) labor-intensive artifact
standard production by National Metrology Institutes (NMIs) and (2)
repeated costly laboratory measurement comparisons associated with mutual
recognition agreements.
For more than three decades the Division has provided a suite of Optical
Filter Standards for validating the absorbance/transmittance scale and
calibrating the wavelength scale of spectrophotometers from the near
infrared through the ultraviolet spectral region. Current efforts are
directed to developing a more cost-effective steady-state support structure
for customers. The approach is to shift the burden of support for the
mature technologies to the commercial sector and intrinsic standards
in order to dedicate limited Division resources to emerging applications
of near infrared and Raman technologies (for process chemistry) and
fluorescence spectroscopy (for biotechnology). A paradigm is envisioned
in which appropriate SRMs are not supported in perpetuity, but are produced
through enough cycles to establish the material as an intrinsic standard
or transfer the continued production to the private sector with an acceptable
traceability strategy. A specific step in this direction resulted from
our publication of band positions of dilute acidic holmium oxide solution
as an intrinsic wavelength standard. These values were determined from
results of an international comparison involving fifteen institutions
(fourteen National Metrology Institutes). In a related development,
CSTL researchers have developed an algorithm to implement holmium oxide
solution wavelength calibration and a proposed extended use of the material
as a universal simultaneous standard for both wavelength and absorbance.
VI. International Standards Activities
International agreements and decisions concerning trade and our social
well being are increasingly calling upon mutual recognition of measurements
and tests between nations. The absence of such mutual recognition is
considered to be a technical barrier to trade and environmental and
health-related decision-making. In recent years, mutual recognition
agreements have been established related to testing and calibration
services and in respect of the bodies accrediting such activities. All
of these rest upon the assumption of equivalence of national measurement
standards and reliability of the link between national measurement standards
and the relevant testing services in each country. In October 1999,
the Directors of National Metrology Institutes for the thirty-eight
member states of the Meter Convention signed the mutual recognition
arrangement on national measurement standards and calibration and measurement
certificates issued by national metrology institutes (MRA); twenty-two
additional signatories have joined in since. This MRA provides an open,
transparent, and comprehensive framework for obtaining reliable quantitative
information on the comparability of metrological services provided by
the signatory NMIs. It also provides governments and other parties with
a secure technical foundation for wider agreements related to international
trade, commerce, and regulatory affairs. Signatories to this MRA have
some very special responsibilities:
- declaring and documenting their calibration and measurement capabilities
(CMCs in Appendix C of the MRA)
- participating in relevant international comparisons to benchmark
the claims made in the CMCs (MRA Appendix B)
- documenting the existence of a system for assuring the quality of
the measurement services provided.
NIST has taken a leadership role in the International Committee of
Weights and Measures-Consultative Committee on the Quantity of Material
(CCQM) and the Chemical Metrology Working Group of the Interamerican
System for Metrology (SIM) in order to assure the effective, fair and
metrologically sound implementation of this MRA. The CCQM has seven
working groups: (1) Gas Analysis, (2) Organic Analysis, (3) Inorganic
Analysis, (4) Electrochemistry (5) Biometrology, (6) Surface Analysis
and, (7) Key Comparisons. These working groups are responsible for selecting
and overseeing the operation of key comparisons that address chemical
measurement-related issues important for international trade, environmental,
health, and safety-related decision making. Analytical Chemistry Division
staff are leading various activities within five of the seven working
groups and Chairing the Organic Analysis Working Group.
The BIPM database includes approximately 3000 CMCs for chemical measurements.
About 1000 will be from NIST. During the past six years, approximately
96 comparison studies have or are being conducted under the auspices
of the CCQM to underpin CMC claims. The Analytical Chemistry Division
has participated in ~80 of these, serving as Coordinating Laboratory
in ~>40.
Participation in CCQM Key Comparisons is available only to top-tier
NMIs around the world. Within the Americas, only the U.S., Canada, and
Mexico have well-established programs in chemical metrology. In order
to most effectively address the unique needs of all 32 countries within
SIM, whose capabilities in chemical metrology span a very broad range,
we have initially focused the SIM program on training and capability
assessment rather than participation in MRA-driven Key and Supplemental
Comparisons. During the past three years, eight intercomparison exercises
were carried out to assess the proficiency of SIM NMIs and/or their
designated laboratories. Five additional exercises are planned for 2005.
While SIM is focusing entirely on training and capability assessment,
Regional Chemical Metrology Working Groups in Europe and the Asian Pacific
are forging ahead and conducting MRA-driven Key Comparison Studies.
We have established agreements with the Chemical Metrology Working Group
Leaders of both regions to allow non-CCQM member countries within SIM
to participate in such studies as soon as they feel competent to do
so. Once self-assessed capabilities of SIM member states are at an appropriate
level, as determined based on performance in the SIM capability assessment
studies, they can also request permission to participate in CCQM Comparisons.
In addition to these global and regional activities, we are also establishing
a limited number of strategic bilateral collaborations and intercomparisons
with NMIs around the world. For example, our collaboration with the
Netherlands Measurement Institute (NMi) for determining the equivalence
of primary gas standards has resulted in a formal "Declaration
of Equivalence" that is recognized by the U.S. EPA and European
environmental regulatory bodies as documenting the equivalence between
seven NIST and NMi primary gas mixture suites. Our formal agreement
with NRC-Canada (via the NAFTA Treaty) for cooperation in marine environmental
studies has fostered collaborations between the U.S. and Canada in the
certification of a several certified reference materials important for
trade and environmental decision-making. We have signed a Cooperative
Arrangement with the National Metrology Institute of Japan for collaborative
efforts in the area of pure volatile organic compound standards. These
highly pure reference compounds will serve as primary references for
many of our gas mixture SRMs. Several additional strategic bilateral
arrangements with other National Metrology Institutes /Standards laboratories
are being discussed.
VII. Collaborations with Other Government Agencies and Professional
Organizations
Providing chemical measurement quality assurance services in support
of other Federal and State government agency programs (on a cost reimbursable
basis) continues to be an important part of our measurement service
delivery portfolio. During the past year, we were involved with about
30 projects with 12 federal and state government agencies. The most
prominent of these other agencies programs, based on level of funding,
are described below:
· National Institutes of Health/Food and
Drug Administration (NIH/FDA) - In 2002 a collaborative effort
was begun with the Office of Dietary Supplements (ODS) within the National
Institutes of Health (NIH) and the Food and Drug Administration (FDA)
to develop SRMs for use in validating analytical methods for chemical
characterization of dietary supplements. This program is a multi-year
effort (six years minimum) designed to provide SRMs for 8-10 selected
dietary supplement materials such as ephedra, ginkgo biloba, St. Johns
wort, saw palmetto, and green tea. NIH-ODS and FDA have identified high-priority
dietary supplement materials for which SRMs will be developed, and NIST
will prepare the reference materials and certify the concentrations
of the active and/or marker compounds as well as contaminants in plant
material, commercial extract, and finished product SRMs. This year,
our on-going collaboration on development dietary supplement SRMs was
expanded to include multivitamin/multielement dietary supplements. NIH-ODS
is collaborating with the U.S. Department of Agriculture (USDA) to establish
the Dietary Supplement Ingredient Database (DSID). The DSID project
will report the results of a systematic survey of supplement composition,
including chemical analyses of ingredients and indicators of data quality.
The initial focus of the DSID project will be on vitamins and mineral
supplements. SRM 3280 is a Multivitamin/Multielement Tablet formulation
that will have NIST Certified and Reference Values assigned for the
18 elements and 15 vitamins/carotenoids to be listed on dietary supplement
labels.
· National Oceanic and Atmospheric Administration
(NOAA) - The Division has had a long history of involvement with
NOAA related to environmental specimen banking and quality assurance
activities. For example, we have coordinated quality assurance programs
for organic and trace metal contaminants in the marine sediments and
tissue for more than ten years
· Department of Justice through NIST Office
of Law Enforcement Standards (OLES) - During the past year, the
Division had several projects supported by OLES including the development
of forensic SRMs (ethanol in water, arson test mixture, and drugs of
abuse in serum), and the evaluation of drug spray reagent test kits.
In late FY03 OLES requested assistance from the Division in the physical
and chemical testing of pepper spray canisters and these efforts continued
this year.
In a totally separate activity for the National Institute of Justice,
the Division's Microfluidics Team is designing an automated miniaturized
DNA analysis system based on microfluidic technology that will be capable
of simultaneously analyzing 16 individual samples for forensic applications.
· Environmental Protection Agency (EPA)
- The U.S. EPA has plans to publish a regulation that requires analysis
of coal fired power plant emissions to determine adherence to a maximum
emission rate. This regulation went into effect in December of 2003
The Division's Gas Metrology team has developed a suite of primary standards
for mercury in air to underpin measurements of mercury measurements
and to facilitate "fair trading" of these emissions in the
future.
In 2000, a new program was initiated with EPA to provide quality assurance
and reference materials to support measurements of organic components
in air particulate matter less than 2.5 mm in diameter (PM2.5). As part
of this program, a third NIST QA program for contaminants was initiated,
the NIST/EPA Intercomparison Program for Organic Contaminants in PM2.5
Air Particulate Matter. This program currently has 25 laboratories participating
in two interlaboratory studies for organic constituents in air particulate
matter. This program will continue through FY04. For development of
an SRM for organic contaminants on PM2.5 we have started a collection
of PM2.5 at a site in Baltimore MD. The goal is to collect approximately
200 g of material by late 2004 for the SRM. Because the collection and
production of a PM2.5 SRM will require several years, an "interim
reference material" has been prepared from 20g of PM2.5 collected
at the same site in Baltimore. Characterization of the organic and toxic
metal content of this material is currently in progress with measurements
at NIST and as part of the intercomparison exercise described above.
· Defense Threat Reduction Agency (DTRA)
- The Division and CSTL have had a long-term association (~10 years)
with this agency to provide chemical consultation and peer-review of
analytical methods and data to support chemical weapons treaty verification.
· Department of Homeland Security
- The Department of Homeland Security has requested that the Division
provide ongoing consultative services in the general area of standards
for chemical measurements. Additionally, efforts have been initiated
for developing a Particulate Reference Material for Quantitative Analyses
of High Explosives and a Validated Instrument-Independent Raman Libraries
for Forensic and Homeland Security Applications to provide both the
physical standards and the validated Raman spectral libraries necessary
to impart confidence in Raman measurements, provide measurement traceability
to national standards, and ensure evidentiary acceptance of Raman measurements.
Potential law enforcement and security customers include the FBI, DEA,
ATF, TSA, Customs, state and local police departments and hazmat teams.
· Centers for Disease Control and Prevention
(CDC) - A long-term program has been established with CDC to
provide QA support for their NHANES and similar epidemiological and/or
monitoring programs. Activities for the past year included:
o Frozen Urine SRM certified for arsenic speciation and trace elements;
o QC Materials for cyanide in frozen whole blood;
o QC Materials for fat-soluble vitamins, carotenoids and vitamin C
in serum;
o SRM for homocysteine and folate in serum;
o two new human serum SRMs certified for organic contaminants;
o a Speciated Arsenic in Urine SRM.
We also had technical interactions that involve laboratory research
and measurement activities with more than 20 professional organizations,
trade groups, and societies including the American Industry/Government
Emissions Research consortium (AIGER), American Association for Clinical
Chemistry (AACC), American Society for Testing and Materials (ASTM),
Certified Reference Materials Manufacturers Association (CRMMA), the
International Federation of Clinical Chemistry (IFCC), National Food
Processors Association (NFPA), National Council on Clinical Chemistry
(NCCLS), and the National Environmental Laboratory Accreditation Council
(NELAC). Specific details concerning many of these interactions are
provided in the Group Sections of this Overview.
VIII. Future Measurement and Standards Activities
We will continue our strategy of maintaining core competencies in chemical
measurement science to address measurement problems in areas of national
priority. All Division research and service projects will continue to
be reviewed on an annual basis for match to mission, progress, quality,
and match to customer needs. Projects in several new areas are being
initiated or expanded.
In the Forensics Standards area, we are working with CDC to provide
quality assurance and measurement proficiency assessment for the "Chemical
Counter-Terrorism Laboratory Network" which is be comprised of
several state public health laboratories and the CDC. In the event of
a chemical terrorism attack, samples (urine or blood) would be shipped
to CDC for analysis to determine what agents were used, who was exposed,
and how much exposure occurred. CDC itself would most likely not be
able to handle so many samples in a short time and would need the help
of the state labs in the analyses. NIST's responsibility is to provide
Reference Materials and QA samples to assist CDC in assuring the quality
of results from such tests. In addition, Division activities concerning
detection of toxins in the water supply and the establishment of a mass
spectral database to facilitate rapid and unambiguous identification/detection
of pathogens are being expanded to address Homeland Security issues.
The primary focus of the Division's component of CSTL's Food Safety
and Nutrition Program is being shifted from populating the AOAC Food
Triangle with food-matrix reference materials (to address nutritional
labeling issues) to reference methods and standards to address consumer
safety and truth-in-labeling issues associated with Nutraceuticals/Herbal
Supplements.
A variety of botanical-containing products are marketed as dietary supplements;
common examples include St. John's wort, ephedra, and gingko. Taxonomically
authentic botanical reference materials with assigned values for active
and/or marker compounds are needed for quality assurance of analytical
measurements associated with the manufacturing process and for the verification
of manufacturers' label claims for the dietary supplement industry.
Assigned values for contaminants and adulterants are also necessary
to address public health and safety concerns. Priorities for activities
in this new project area are being set in consultation with the U.S.
Food and Drug Administration, and the National Institutes of Health's
Office of Dietary Supplements.
Our research project on Microfluidic Devices, methods, and applications
for chemical analysis including studies of materials and material properties
affecting the flow of liquids in microchannels will begin to focus more
on the use of microchannel and other electrophoretic methods for forensic
and toxicological applications and standards. Research in our new Competence
area, Single Molecule Measurements and Manipulations will be expanded.
Additional details concerning the latter two research activities are
provided in the Group Sections of this Overview that follow.
Healthcare is a major focus area for NIST, the Chemical Science and
Technology Laboratory and the Analytical Chemistry Division. The goal
of obtaining comparability of laboratory diagnostic test results will
be possible only when common reference systems can be established for
worldwide use. A critical step in reaching this goal is achieving traceability
of reference measurement procedures and reference materials to a universally
recognized and accepted reference point such as the International System
of Units (SI). Recently, traceability requirements for medical devices
to be imported into the European Community have been codified. The European
Community In Vitro Diagnostic Directive (EC IVDD) states that "The
traceability of values assigned to calibrators and/or control materials
must be assured through available reference measurement procedures and/or
available reference materials of a higher order." (98/79/EC, Annex1
(A) (3) 2nd paragraph). The Joint Committee on Traceability in Laboratory
Medicine (JCTLM) was created to meet the need for a worldwide platform
to promote and give guidance on internationally recognized and accepted
equivalence of measurements in Laboratory Medicine and traceability
to appropriate measurement standards. At present, neither reference
materials nor reference methods are available for the vast majority
of the chemical or biochemical species that are measured in medical
laboratories using IVDs on a routine basis. We are committed to work
with the JCTLM in the development of new reference methods and blood/urine-based
CRMs for several new health-status markers while maintaining previously
developed reference systems for calcium, chloride, cholesterol, creatinine,
glucose, lithium, magnesium, potassium, sodium, triglycerides, urea,
uric acid, and vitamins A, C, E and beta carotene as well as several
therapeutic drugs and drugs of abuse.
While focusing increased attention on the health-care/clinical diagnostics
area over the next 3-5 years, we will still provide renewals of existing
SRMs that support measurements in areas critical to the global community
and address critical measurements and standards needs in new high priority
areas such as:
We expect that the NTRM approach will continue to expand as the basis
for allowing the commercial sector to provide reference materials to
end-users with a well-defined traceability linkage to NIST. High quality
SRMs will continue to be developed to address both national and international
measurement problems, but they will be much more expensive and targeted
for purchase primarily by other national metrology institutes and commercial
producers/distributors. Increasingly, end-user needs will be met via
NIST-traceable commercially produced reference materials.
The complex nature of chemical measurements coupled with the increasingly
global nature of trade, health, and environmental issues speaks to the
need for having the world make measurements using a common "meterstick."
The comprehensive nature of the NIST program in chemical measurements
puts us in position to make a very significant contribution to the international
chemical measurements community in this regard. In order to do this
in both a cost-effective and internationally congenial manner, we are
investigating opportunities for partnering with other highly qualified
NMIs to provide high quality Certified Reference Materials in specific
standards areas. Potential advantages of these proposed partnerships
include increased supply, breadth and quality of reference materials
for the worldwide chemical measurements community as well as less duplication
of effort for more efficient use of limited resources.
This Division overview plus the Group-specific sections and Selected
Technical Activity Reports that follow provide additional details concerning
our work and reflect the high quality of our staff. This information
also shows how our efforts are impacting U.S. industry's productivity
and competitiveness as well as providing the measurement and standards
infrastructural support for environmental quality and human health assessments.
The Overview and Reports also illustrate the critical synergistic relationships
that exist among our research programs in chemical measurement science
and the standards and quality assurance services that we provide to
our customers.
IX. Group Overviews
Spectrochemical Methods
Research activities in spectrochemical methods are directed toward the
development, critical evaluation, and application of techniques for
the identification and measurement of inorganic species using x-ray,
optical, and mass spectrometries. The focus of this research is measurement
accuracy and precision, benchmarking industry's needs for traceability,
advanced materials characterization, and commodity value assignment
and specification.
A significant portion of the Group's research and measurement activities
help maintain the Nation's healthcare measurement infrastructure by
developing and maintaining reference methods and materials for electrolytes
and toxic metals in clinical matrices. In FY03 NIST issued SRM 2670a,
Toxic Elements in Freeze Dried Urine, a much-improved replacement SRM
developed in collaboration with the Centers for Disease Control and
Prevention and the Mayo Clinic. The new SRM is now being used as an
important quality assurance tool for CDC population surveys of toxic
element exposure. In FY04, we replaced NIST SRM 956a, Electrolytes in
Frozen Human Serum, with SRM 956b. This SRM series is widely used for
the calibration and validation of automated analyzers and electrolyte
measuring systems based on ion selective electrodes. The potential impact
of these SRMs is well illustrated by a recent report, commissioned by
NIST, on laboratory testing of calcium in serum. This report concluded
that the potential economic impact on the health-care system of even
a modest analytical bias could lead to an annual cost of $60M to $199M
resulting from unnecessary follow-up patient testing. The new serum
SRM was certified using recently updated NIST methods based on ICP-MS
rather than Thermal Ionization MS. Noteworthy is the new ICP-MS method
for lithium, which was a particular challenge because of significant
mass bias drift found for lighter elements and inter-sample memory effects.
The updated methods for electrolyte determinations in clinical samples
have been compiled as a NIST 260 Series Report, currently undergoing
NIST editorial review.
In December of 2003 the European Union Directive on In-Vitro Diagnostic
(IVD) went into effect mandating IVD traceability to "higher order"
standards and methods. Sales of NIST electrolyte in serum SRMs have
increased dramatically in response, as has the needs of U.S. IVD manufacturers
for higher-order reference measurements. With the goal of building an
efficient infrastructure for providing clinical reference measurements
for IVD manufactures, NIST entered into a collaboration with Mayo Clinic
and Dade-Behring, Inc. to test procedures that might be used to implement
a NIST Traceable Clinical Reference Laboratory Network. Such a network
could provide the IVD industry with reference measurements traceable
to NIST standards in a timely and efficient manner. The specific test
conducted involved the measurement of calcium at various levels in blood
serum, plasma, and urine. A subset of real samples of serum, plasma,
and urine were measured both at NIST and the Mayo Clinic, using NIST
calibration and validation SRMs, in order to establish an equivalence
between NIST isotope dilution mass spectrometry measurements and measurements
performed at Mayo Clinic. Initial results have been encouraging, and
could potentially lead to the development of a network of laboratories
with an expanded analyte and matrix coverage.
In FY03, the Spectrochemical Methods Group, with much collaboration
with the Organic Analytical Methods Group, began a major research activity
in the area of metal speciation, with a variety of healthcare and environmental
projects planned. Two new LC-ICP-MS systems to allow sensitive metal
specific detection of separated species were installed-one each both
our Gaithersburg and Charleston facilities. FY04 has seen much progress
in this area. A new GC-ICP-MS was designed and built in Charleston,
and has already been used to develop a new and very sensitive method
for the determination of organo-mercury compounds. The new GC-ICP-MS
method was used to value assign the methyl mercury concentration in
SRM 966, Toxic Elements in Bovine Blood, and will result in an update
of the Certificate of Analysis for this SRM. Such an update has been
greatly sought by CDC. In Gaithersburg, the new LC-ICP-MS system has
been used to investigate arsenic valence state variations in SRM 3103a,
the arsenic spectrometric calibration solution SRM. The study confirmed
that various lots of the SRM have different distributions of As III
and As V, that these differences can cause biases in ICP-MS and ICP-OES
measurements, and that these differences result from slower than expected
kinetics in the acid digestion of arsenic metal used to prepare the
SRM. A separate research project is developing a LC-ICP-MS measurement
method for selenoproteins in clinical samples. Back in Charleston, both
GC-ICP-MS and LC-ICP-MS measurements of arsenic, tin, selenium, and
mercury species in various existing SRMs and marine tissue samples are
being made.
In the area of homeland security we have completed and implemented
the development of an isotope dilution GC-MS method for the determination
of cyanide in blood. This project was undertaken to enable the development
of quality assurance and measurement proficiency standards for the CDC
Laboratory Response Network for Chemical Terrorism. This laboratory
network was developed by CDC to provide rapid measurement support in
the event of a terrorist chemical attack. This new method has been adopted
by CDC, and an interagency agreement between NIST and CDC has been put
in place to value assign and test the stability of commercially prepared
proficiency testing samples of frozen human blood spiked with cyanide
at various concentrations.
Three years ago researchers within the Group achieved a breakthrough
in the area of high-accuracy measurement of mercury at both trace and
elevated levels with the development of an isotope dilution cold vapor
ICPMS methodology. This work was recognized with the R&D Magazine
award for being one of 100 notable innovations in 2001. After seeing
the announcement of this award, NIST was contacted by the Department
of Energy to help provide data that could affect impending regulation
of mercury concentrations in crude oil at U.S. petroleum refineries.
As it turns out, information regarding typical concentrations of mercury
in crude oil is scant, and the levels are low enough that the accuracy
of existing measurements can be considered questionable. As a means
of assessing the typical concentrations of crude petroleum streams which
find their way into U.S. refineries, we were asked to undertake a study
of mercury concentrations in samples selected from the U.S. Strategic
Petroleum Reserve. Thus far nearly 100 samples have been studied, and
the results indicate that levels are an order-of-magnitude or more lower
than estimates based on older measurements. This new information is
likely to impact decisions regarding the need for regulation of mercury
in crude oil. The Department of Energy continued and expanded this project
in FY04.
The Group maintains strong ties within many U.S. industrial sectors
through its active participation in various committees of ASTM and ISO.
Contacts and interactions developed through these activities help guide
decisions regarding the development of new SRMs and the renewal of existing
SRMs. Listed below are brief summaries of several recent SRM certification
projects to provide national standards to underpin important measurements
in aerospace, automotive, agriculture, food packaging, steel, cement,
construction, and mining industries.
· Suite of Six Aluminum Alloy SRMs
- (SRM 853a, SRM 854a, SRM 1240c, SRM 1241c, SRM 1255b, SRM 1256b).
A total of 15 elements were determined in these SRMs using Glow Discharge
Optical Emission Spectrometry for the first time for NIST certification
measurements. These SRMs are benchmark materials for several important
aluminum alloys: 3004 (SRMs 853a and 1240c), 5182 (SRMs 854a and 1241c),
356 (SRM 1255b, and 380 (SRM 1256b). All of these alloys have varied
infrastructural uses and are represented in automobile manufacture,
for instance, from body parts to engine components. The aluminum industry
has sophisticated in-house reference materials programs to supply their
plants and customers with well-characterized materials for product quality
control and business transactions. These SRMs serve as the benchmarks
to underpin industry reference materials.
· SRM 173c, Titanium Alloy - This
alloy is one of a small list of high value, high production Ti alloys
that are important products of the US and world titanium industry.
· SRM 1d, Limestone - Arg Argillaceous
limestone is a basic commodity that is used in the production of steel
(roughly 50 kg is added per 1000 kg of steel). The chemistry of the
added limestone is an important factor in the quality of the steel production.
Limestone also finds important uses in agriculture and building materials,
and the renewal of this SRM was strongly advocated by several industrial
sectors via ASTM.
· SRM 2696, Silica Fume - Silica
fume imparts resistance to corrosion and adds strength to concrete;
it has an estimated billion-dollar impact on our national infrastructure.
Once an expensive waste byproduct of silicon and ferrosilicon production,
it also has an environmental impact. Every ton used in concrete reduces
the greenhouse gas output of the cement industry, which releases CO2
during cement manufacture. A number of national standard specifications
for silica fume are being implemented in the United States, Canada,
Europe, Japan and Australia. The silica fume SRM will be used by the
construction industry, silica fume producers and over 60 state and federal
agencies (mostly state highway administrations) to verify specifications
of silica fume before it is admixed into concrete. Demand for this SRM
is driven by its unique physical and chemical properties as well as
its economic impact. Quantitative XRF analyses were completed at NIST
using a matrix-independent methodology developed a few years ago.
· Crystalline Silica on Filter SRMs
- A series of SRMs undertaken at the request and with funding provided
by NIOSH and OSHA to provide a basis for the comparability of results
from various laboratories to monitor mine safety conditions.
The group has a small but potentially important research effort to
utilize our High Performance ICP-OES capabilities to determine the stoichiometry
of crystalline materials with high accuracy and precision. Aluminum
gallium arsenide (AlGaAs), used in optoelectronic applications, was
studied in collaboration with EEEL. Another collaboration with EEEL,
this time for the measurement of AlGaN, is planned for FY05. In collaboration
with the Surface and Microanalytical Research Division we have also
studied SiGe, a material that is being applied in wireless communication
and computer applications. In the latter project, the major effort was
the development of an accurate means of dissolving the sample for ICP-OES
analysis.
Throughout the world spectrochemical instrumentation is calibrated
using elemental solution standards that most laboratories purchase from
commercial suppliers. In most, if not all, cases these commercial standards
assert traceability to NIST, which translates to traceability to the
SRM 3100 Series of 69 single-element solution standards certified for
the mass fraction of the element in solution. This SRM series therefore
plays a key role in the overall calibration infrastructure for elemental
analysis, and these SRMs directly affect the results of millions of
analyses performed around the world. The ability to maintain this large
and critical suite of SRMs certified and in stock has been a challenge
for many years, and a key element in making this task feasible is the
shelf life of the SRM. For the past three years the main activity in
the maintenance of this SRM series has revolved around testing the stability
of the existing SRM stock, looking to extend certification periods rather
than discarding and replacing stock. New data on the transpiration of
water through the walls of the plastic containers used for many of the
SRMs collected over the past three years indicates that the rate of
transpiration is negligible when the containers are sealed in aluminized
mylar pouches, as they have been for several years. Since transpiration
results in a change of the element mass fraction, this new evidence
of the lack of transpiration has allowed us to extend the certification
period.
The Group's activities at the Hollings Marine Laboratory in Charleston,
SC have expanded with the addition of new staff. Activities are centered
on providing a quality assurance infrastructure for marine environmental
monitoring projects, often in collaboration with state and other federal
government agencies. As part of our collaboration in the Seabird Tissue
Archival Monitoring Project with the U.S. Fish and Wildlife Service,
the Alaska Maritime National Wildlife Refuge, and USGS we have analyzed
various sets of sea bird eggs collected in Alaska for mercury concentration
using our high accuracy isotope dilution method. Another activity is
the Dolphin Health Assessment Project in collaboration with the National
Marine Fisheries Service, the Mote Marine Laboratory, and the Chicago
Zoo, for which we have developed blood sampling protocols for trace
element determinations and accurate high throughput methods for the
determination of trace elements in marine animal blood. Further studies
include a multi-agency program to develop and apply protocols to investigate
the cause of the increase in debilitated sea turtle strandings and a
project with the College of Charleston funded by SC Sea Grant on the
use of diamondback terrapins as a sentinel species for monitoring mercury
contamination in estuarine systems. The second round of the NIST National
Marine Analytical Quality Assurance Program for trace metal analysis
is nearly complete with the preparation, value assignment and distribution
of new whale liver homogenate QC materials to 31 participating laboratories,
data compilation and analysis, and the issuance of a draft report to
participants.
Many of the above Group activities have been benchmarked against the
measurement capabilities of other national metrology institutes through
our participation in the Inorganic Analysis Working Group of CCQM. Our
capabilities to perform measurements of metals and alloys were tested
through a pilot study (P-34) on the determination of constituent elements
in aluminum alloy, and a key comparison (K-33) on minor elements in
steel. The aluminum alloy work will continue as a Key Comparison in
FY05. We also served as the coordinating laboratory for the Key Comparison
K-35 on the measurement of low sulfur in diesel fuel was run concurrently
with a pilot study (P26.1) on the measurement of very low (~10 ppm)
sulfur in kerosene. Both of these studies were designed to demonstrate
NMI measurement capabilities needed to meet current and near-future
regulatory limits on low sulfur concentrations in fuels. The regulatory
push to lower sulfur concentrations is needed in order to enable extremely
efficient and long-lived after-treatment emission technologies, primarily
catalytic converters. The need for these after-treatment systems is
being nationally and internationally mandated by regulatory actions
seeking to reduce the level of nitrogen oxides and non-methane organic
gases, which are the primary emission pollutants from internal combustion
engines. In addition, we are coordinating a pilot study (P46) that compares
the primary elemental solution standards of participating NMIs. These
solutions are prepared by participants and sent to NIST where a relative
comparison of element content relative to the prepared solution concentration
is made using our high-performance ICP-OES methodology. Measurements
are ongoing, and include solutions of copper, magnesium, and rhodium.
Nuclear Analytical Methods
Research activities in this group are focused on the science that supports
the identification and quantitation of chemical species by nuclear analytical
techniques. Current laboratory research activities involve the full
suite of nuclear analytical techniques based on reactor neutrons, including
instrumental and radiochemical neutron activation analysis (INAA and
RNAA), prompt gamma activation analysis (PGAA), and neutron depth profiling
(NDP). In addition, we are developing analytical applications of neutron
focusing technology. The measurement capabilities that reside within
this group provide an excellent complement to those in the Spectrochemical
Methods Group in that nuclear analytical methods depend upon characteristics
of the nucleus of the element rather than the electron shells, and therefore
are insensitive to the chemical state of the analyte. In addition, the
nuclear methods are generally nondestructive and do not require sample
dissolution, thus providing an independent assay. NDP and focused beam
PGAA provide unique capabilities at NIST for location sensitive analysis
and elemental mapping.
INAA and RNAA are powerful reference techniques that have been used
at NIST for many years. New developments continue to provide improvements
in detection sensitivities, elemental specificity, precision, and overall
accuracy that allow nuclear methods to address new measurement needs.
During the last several years, we have been involved in demonstrations
that instrumental neutron activation analysis meets the CCQM definition
of a primary ratio method of measurement. Our first step was to characterize
all sources of uncertainty for INAA measurements and develop the tools
to establish a complete uncertainty statement in terms of SI units.
We next applied INAA as a primary method for certification of the arsenic
content of SRM 2134, Arsenic Implant in Silicon. The INAA results used
for this certification included the first complete, quantitative evaluation
of all sources of uncertainty in an INAA measurement. The expanded relative
uncertainty for the mean value of this SRM was 0.38 % and approximates
the 95 % level of confidence.
In measurements for the NIST Surface and Microanalysis Science Division
(837) similar low uncertainties were required for the determination
of germanium in silicon. Silicon germanium can be epitaxially grown
on silicon resulting in alteration of numerous physical and electronic
properties and improved performance of transistors and circuits. It
allows for increases in chip speeds of up to 35% while reducing their
power consumption. IBM projects that SiGe technology will be dominant
in the wireless semiconductor market, growing to a $3 billion market
in 2005. The need for compositional reference materials for secondary
ion mass spectrometry (SIMS) analysis was indicated at a SIMS workshop
held in 2001. This work was undertaken to assist in the development
of such standards. Three different bulk alloy samples were acquired
from Virginia Semiconductor. The samples have been characterized for
homogeneity by extensive conventional electron microprobe work. Two
samples, SiGe6.5 and SiGe14, were found to be suitable for use as microprobe
standards. ICP and INAA work has been done on test samples from the
3.5%, 6.5% and 14% alloy. Preliminary measurements indicated that relative
expanded uncertainties of several tenths of a percent should be achievable
by INAA. However, a significant trend in the analytical data was discovered
as a function of decay time; this prompted a re-evaluation of the half-life
for 77Ge. A new value about 1% less than the literature value was found.
When the new half life was this was introduced into the INAA calculations,
excellent agreement was observed for all measured data. Considering
that our half-life measurements were not yet independently validated,
the uncertainty in the decay parameters remained a significant component
in the expanded uncertainty of the final reported values: Ge3.5: (4.177
± 0.025) mol Ge / mol Si (0.59%), Ge6.5: (6.455 ± 0.041)
mol Ge / mol Si (0.63%), and Ge14: (14.360 ± 0.092) mol Ge /
mol Si (0.64%).
Recently developed new INAA procedures for small sample analysis have
been applied in the certification of SRM 2703 Inorganics in Marine Sediment
for Solid Sampling Analysis. The innovative SRM has been developed to
serve the many analytical techniques used in industry and academia,
which rely on the analysis of very small samples (i.e., 1 mg), typically
in the solid (undissolved) form. Taking advantage of the sensitivity
and nondestructive properties of INAA, the use of this technique for
homogeneity studies of small samples has been evaluated and implemented
for the determination of sampling characteristics for a number of environmental
SRMs. The small analytical uncertainty associated with the INAA measurements
allows extraction of the variability due to material inhomogeneity from
the observed total variability within a given set of measurements. Based
on the evaluation of three sediment materials that previously have shown
the potential for a high degree of homogeneity at very small sample
sizes, we have processed a portion of sediment from the Baltimore Harbor,
previously certified for "normal" sample sizes (SRM 2702)
constitute SRM 2703. We have achieved a finely powdered sample with
a median particle size of 3.5 µm with no particles exceeding 20
µm in diameter. The excellent homogeneity that had been expected
from this processing has been confirmed with INAA determinations of
minor and trace elements in 0.7 mg samples. We have observed relative
standard deviations of 0.9 % for Al and 1.8 % for V, for example, in
22 samples of this material. Certified values have been assigned based
on the NIST-INAA determinations of 22 elements in 0.7 mg samples of
SRM 2703, and the results obtained from collaborators with similar INAA
procedures as well as other solid sampling techniques including GFAAS,
laser ablation or slurry sampling ICP-MS, and microbeam-XRF and -PIXE.
Analytical evidence of equivalency in mass fraction values of SRM 2703
and the parent material SRM 2702 allowed us to broaden the analytical
basis and consider the certification values of the latter for value
assignment in SRM 2703.
Radiochemical neutron activation analysis has proven to be a powerful
tool for measuring trace phosphorus in a variety of materials. An RNAA
procedure has been developed to determine and value assign phosphorus
in various SRMs. Phosphorus is quantified by beta counting of 32P after
radiochemical separation. Originally developed for the analysis of metals,
the method was used to value assign phosphorus in SRMs 861 (Aircraft
Superalloy) and 2175 (Refractory Alloy), both containing phosphorus
at low mg/kg levels. Modifications to the procedure have allowed us
to value assign phosphorus in two new SRMs: 1575a (Pine Needles) and
2702 (Inorganics in Marine Sediment). RNAA was also used for the first
time as a primary method to certify the ion implanted phosphorus dose
in SRM 2133, Phosphorus Implant in Silicon. This material has been a
continuing high-priority need of the semiconductor industry for many
years, and is intended for use as a calibrant for secondary ion mass
spectrometry (SIMS). It has been produced and certified in collaboration
with the Surface and Microanalysis Science Division.
RNAA methods are also being developed and evaluated for measurement
of low-level sulfur and nitrogen in steels. Irradiation with thermal
neutrons produces 35S and 14C (both pure beta emitters) from sulfur
and nitrogen via the 34S(n,d)35S and 14N(n,p)14C reactions. These nuclides
are separated from the matrix and quantified by liquid scintillation
counting. Preliminary measurements indicate detection limits of 5 ng/g
and 30 ng/g for S and N respectively in 1 g of low alloy steel irradiated
for 8 h at 3 x 108 cm-2s-1. If successful, these procedures may be adapted
for measurement of S and N in other materials. Development of methods
for low-level measurement of these elements could impact numerous industries,
including the U. S. aerospace industry, which requires primary standards
for accurate measurement of these elements in alloys.
Delayed neutron activation analysis (DNAA) is being established at
NIST for the measurement of small quantities of fissionable nuclides
such as 235U and 239Pu. DNAA is rapid, specific, matrix independent,
nondestructive, and sensitive. The system being built at NIST is calculated
to have a detection limit for either of these species about 10 picograms,
based on a straightforward extrapolation from published practice. After
testing uranium standards in two shielding configurations, a final detection
system has been designed and built. This consists of ten neutron detectors
in a 30 x 30 cm cylindrical moderator of polyethylene, lined with 2
cm of lead to absorb gamma radiation. The design incorporates the existing
pneumatic rabbit assembly for irradiation control and sample transport.
The system is able to move the sample rapidly to the neutron detector
through a polyethylene flight tube. The analysis time is less than 2
minutes per sample. On completion and verification, the Nation will
have a readily accessible, rapid means of measuring traces of fissionable
U and Pu in samples of forensic interest. In addition, the specificity
and sensitivity of this method of analysis will be put to use in certifying
trace uranium in Standard Reference Materials.
A method has been developed and apparatus built to produce titanium
(and other metal) SRMs of known hydrogen concentration on the few-kilogram
scale. The method is based on the controlled reaction of hydrogen with
titanium in a closed system. After preparation, the hydrogen concentration
is verified by cold-neutron prompt-gamma activation analysis and gravimetry.
The first SRM, 2453 (Hydrogen in Titanium Alloy) has been prepared near
the critical level of approximately 100 mg/kg. Cold neutron PGAA, neutron
incoherent scattering, volumetry and gravimetry have been used together
to certify a hydrogen mass fraction of 114 ± 5 mg/kg. Two additional
Hydrogen in Titanium SRMs, 2452 and 2454, have now been prepared and
certified at bracketing levels of 62.5 ± 1.6 mg/kg and 211 ±
4 mg/kg respectively. This method has also been used to prepare standards
for neutron-tomographic nondestructive analysis of turbine blades at
McClellan Air Force Base.
Pioneering research is conducted by the Nuclear Methods Group on the
use of cold neutron beams as analytical probes for both PGAA and NDP.
PGAA measures the total amount of an analyte present throughout a sample
by the analysis of the prompt gamma rays emitted immediately following
neutron capture. NDP, on the other hand, determines the concentrations
of several important elements (isotopes) as a function of depth within
the first few micrometers of the surface by energy analysis of the prompt
charged particles emitted during neutron bombardment. Both of these
techniques continue to make important contributions in the characterization
of advanced materials, particularly with the enhanced sensitivities
now available using cold neutrons from the NIST Reactor.
The neutron depth profiling facility continues to provide unique measurement
capabilities directly to US industries. Current experiments of interest
at the NDP instrument include the measurement of lithium concentration
and distribution in thin films being studied for battery applications,
studies of boron mobility in tungsten with the Army Research Laboratory,
shallow-doped boron content in silicon in conjunction with Advanced
Micro Devices, the study of lithium distribution in lithium niobate,
and the measurement of nitrogen in layers such as TiN and GaN.
As recent examples, we have collaborated with Corning Laboratories
on analyses of several high technology materials. One measurement was
of nitrogen concentrations measured in GaN/GaAs bilayers. This material
is a base material for construction of devices such as blue light emitting
lasers. The N concentration, which we can determine quantitatively,
is a crucial parameter for establishing the device characteristics.
However, there are processing issues in the introduction of N at high
levels without causing phase separation. An important need towards that
goal is a reliable, accurate method for N concentration as a function
of depth in GaAs-based alloys. Two other types of samples with Corning
have been analyzed: (1) Boron profiles are measured in glasses to determine
B loss due to its volatilization during manufacturing. Surface depletion
of B is a key characteristic of borosilicate materials for both chemical
vapor deposition and conventional melting processes; and (2) lithium
niobate where a quantitative measure of Li concentration was able to
differentiate congruent and stoichiometric compositions and any surface
depletion in commercial wafers.
We have also measured the nitrogen concentration of MnN/ScN in conjunction
with scientists from the NCNR and Ohio University. MnN is a metallic
anti-ferromagnetic material that can be used with ferromagnetic semiconductors
to make spintronic devices for data storage systems. The magnetic transition
point of thin films made with this material is different from that of
the bulk material. To measure this transition, which occurs at an elevated
temperature, annealing is required. However, the annealing process is
suspected of causing the nitrogen to escape, which in turn changes the
transition temperature. Using NDP, we have determined that the original
films were indeed nitrogen-deficient. Subsequent films were then made
with a ScN layer and were again measured with NDP. These measurements
show that this problem has been corrected. A joint publication on this
work is in preparation. The total film thickness was determined (330
nm) and the total nitrogen concentration to a precision of better than
1% (1?).
Members of the Nuclear Methods Group have also worked on a number of
high priority PGAA projects with more than 20 "outside clients"
as part of our responsibility for supporting the NIST Center for Neutron
Research "National Users" Facility. Many of our current PGAA
collaborations involve determining hydrogen in a wide variety of materials
for different applications. PGAA has been used to measure hydrogen in
semiconductor materials, in barium titanate, in mesorporous carbon,
in glassy carbon plates developed for use in fuel cells, and in various
deuterated polymers. PGAA has also been used to characterize elemental
contents of Ag and Au doped vicor, zeolites, TiO2 used in pigments,
and Ag compounds used in ink jet printers. Native boron has been measured
in silicon as part of a CCQM study. Boron mass fractions near 50 ng/g
were measured. In collaboration with scientists at NASA-Goddard Space
Flight Center, we are helping to develop a method of obtaining spatially
resolved elemental compositions using a focused neutron beam. The goal
is to develop an instrument that could be used to evaluate a planetary
body from a distance of 2 km.
In collaboration with scientists at Johns Hopkins University, PGAA
was used to perform an efficiency calibration of a gamma-ray detector
that will be used by the NASA Messenger spacecraft to map the composition
of the crust of the planet Mercury. The detector will measure gamma
rays emitted by elements in the planet's crust upon capture of cosmic
ray induced neutrons. Efficiency was calibrated as a function of energy
up to 9 MeV using prompt gamma rays emitted from NaCl and chromium targets,
along with gamma rays emitted by calibrated radioisotope sources mounted
in the same configuration. The results will allow the spacecraft to
obtain an accurate compositional map. Messenger was launched this year
and will begin mapping the surface of Mercury in 2011.
We have recently collaborated with Jefferson Laboratory to monitor
the hydrogen content of niobium that is used in the construction of
the accelerator for the Spallation Neutron Source at Oak Ridge National
Laboratory. The presence of interstitial hydrogen in niobium is believed
to have a detrimental effect on its mechanical and superconducting properties.
It is suspected that chemical polishing (acid treatment) used to remove
surface defects from the niobium introduces hydrogen, while vacuum heating
may be used to remove it. We have used prompt gamma-ray activation analysis
(PGAA) and neutron incoherent scattering to study the effects of these
two processes on the hydrogen content of the niobium. The measurements
indicated that both processes can significantly alter the metal's hydrogen
content. The results of these and future studies should lead to significant
improvement in the methods for manufacturing and processing the high
purity niobium used in these cavities.
Plans are underway for reconstructing the cold neutron guide NG7. A
segmentally curved section will be added to move the PGAA sample position
from the present constricted location 3 cm below the SANS guide to the
new end position. This reconfiguration will give greatly lowered background
and improved detection limits, more space in the target area for the
analysis of larger samples, and a much more flexible configuration:
for the first time, the sample area will be accessible when the reactor
is on, allowing use of a sample cryostat, adjustment of collimators
and beam monitor, use of a chopped beam, and an adjustable position
for the neutron lens. With the help of a summer student, a plan has
been devised to make the PGAA and NDP instruments interchangeable at
the new experimental station.
Organic Analytical Methods
Activities in organic analytical methods are directed toward the development,
critical evaluation, and application of methods for the identification
and measurement of organic and organometal species using analytical
separation techniques and mass spectrometry. These separation techniques
include gas chromatography (GC), liquid chromatography (LC), supercritical
fluid chromatography (SFC) and extraction (SFE), and capillary electrophoresis
(CE). These techniques are applied for measurement of organic compounds
in support of development of SRMs, quality assurance programs, and other
agency activities in clinical, food and nutritional, environmental,
forensic, and homeland security areas.
Organic Mass Spectrometry: Recent research activities in organic mass
spectrometry have focused on the development of techniques for characterization
and quantitative determination of organic compounds, including proteins,
in biological matrices. The acquisition of new MS instrumentation in
2003-2004, an LC with tandem mass spectrometry (LC/MS/MS) system, an
LC/MS system, and a matrix assisted laser desorption time-of-flight
mass spectrometer (MALDI-TOF), has significantly increased our capabilities
for the determination of trace-level analytes of health, nutritional,
forensic, and environmental importance, as well as protein characterization.
The second MALDI-TOF was obtained with our increased support for activities
in the Hollings Marine Laboratory in Charleston, SC and will expand
our capabilities for characterizing biomolecules and natural products.
Much of our effort in mass spectrometry research has been applied to
the measurement of health status markers. Levels of specific proteins
and other biomolecules in blood are indicative of certain disease states.
These so called "health status markers" often permit more
rapid diagnosis of disease with greater certainty than is possible by
other methods. Twelve health status markers have been identified as
high priority for immediate studies. Recent efforts have been directed
toward the development of reference methods for troponin I (a new marker
of myocardial infarction), thyroxine and other thyroid hormones (markers
for thyroid function), cortisol (a marker for endocrine function), speciated
iron (how iron is associated with proteins is important for elevated
or low iron levels), homocysteine (a risk factor for myocardial infarction),
folic acid (an essential nutrient that reduces the risks of heart disease
and neural tube defects), and prostate specific antigen (PSA) (a marker
for prostate cancer). Because protein biomarkers occur naturally with
considerable heterogeneity (i.e., with glycosylation, acetylation, phosphorylation),
we have developed LC and MS techniques for chemical characterization
of the target species, particularly the protein-based markers such as
troponin I and PSA.
The Analytical Chemistry Division has a long-standing effort to promote
accuracy in health-related measurements through development of reference
methods and SRMs. With issuance of the in vitro diagnostic (IVD) device
directive by the European Union, it has become even more critical for
NIST to develop new reference methods and SRMs to provide traceability
for the US IVD industry so that this industry can maintain its strong
position in European markets. During the past year, work has focused
on the development of reference methods for these health status markers
based on isotope dilution LC/MS and LC/MS/MS and the completion of critical
new SRMs to address the IVD Directive. SRM 2921, Cardiac Troponin Complex
(see Technical Activity Report) and SRM 1955, Homocysteine and Folate
in Human Serum (risk factor for heart disease and a substance that counteracts
effects of homocysteine) have been completed. Methods development for
selected thyroid hormones in serum have been completed and will be applied
to the certification of an SRM 971 Hormones in Serum. In response to
a need for a better reference material for detection of kidney disease,
work has started on a new frozen serum SRM for creatinine. Three important
clinical SRM renewals were completed this year: SRM 1951b Lipids in
Frozen Human Serum is a two-level material certified for cholesterol
and triglycerides; SRM 956b Electrolytes in Frozen Human Serum is a
three-level material certified for five electrolytes with reference
values for ionized calcium; and SRM 965a Glucose in Frozen Human Serum
is a four-level material with a much wider concentration range than
the previous lot had. These new reference methods and SRMs will help
the IVD industry meet new regulatory requirements for traceability.
Research is continuing on development of a reference method for another
risk factor for heart disease, C-reactive protein (CRP). Modest increases
in CRP have been linked to arteriosclerosis and the increased risk of
heart attacks. NIST, working with scientists at the Laboratory of the
Government Chemist (LGC) in the UK and the Physikalisch-Technische Bundesanstalt
(PTB) in Germany, is using a proteomics approach to isolate characteristic
peptides from CRP for measurement by LC/MS. An isotope labeled peptide
will be used as an internal standard for this work. Research has also
begun to investigate the quantitative potential of MALDI-TOF mass spectrometry
for biomolecules. To explore this potential, studies are underway on
promising approaches for quantification of transferrin, an important
iron-transporting protein in blood. Research is also underway on measuring
various selenium-protein (anti-cancer agents) and iron-protein (iron-transport)
combinations in blood.
Separation Science: Research activities in separation science
continue to focus on investigations of the physical and chemical processes
that influence retention in LC, GC, SFC, CE, and CEC. Results from these
fundamental studies are used to design stationary phases tailored to
solve specific separation and analysis problems, and to assist in method
development and optimization. Recently we have explored a novel approach
to the synthesis of LC stationary phases based on polymer immobilization.
Polyethylene acrylic acid copolymers were immobilized on silica as an
alternative to conventional silane surface modification chemistry. The
resulting columns were evaluated for the LC separation of carotenoid
isomers, and results indicate exceptional selectivity for this class
of compounds, which should result in improved measurement capability
for carotenoids and related nutrients in food and dietary supplement
samples.
Research in chiral separations is continuing in several areas using
LC, CE, and GC. A CE method was developed for the determination of chiral
ephedra alkaloids as part of our development of a suite of ephedra-related
SRMs. The alkaloids of interest consist of pairs of diastereomers that
can be difficult to separate on nonchiral stationary phases.
Our research in organometal speciation has continued with improvements
in our method for methylmercury and alkyltin species. The GC-Atomic
Emission Detection (AED) method used previously to certify several mussel
and fish tissue SRMs has been replaced with an isotope dilution GC-MS
that has been used to provide data for certification of methylmercury
in SRM 1974b Organics in Mussel Tissue and SRM 1947 Lake Michigan Fish
Tissue. Other GC-related separation science research has focused on
improved the methodology for the determination of nitro-substituted
polycyclic aromatic hydrocarbons (nitro-PAHs) and high molecular weight
PAHs in environmental matrices. For the nitro-PAHs a normal-phase LC
isolation of the nitro-PAHs was implemented prior to measurement by
GC/MS with negative ion chemical ionization detection. An improved separation
of the isomeric nitro-PAHs, particularly the nitropyrene and nitrofluoranthene
isomers, was achieved using a 50% phenyl-substituted methylpolysiloxane.
This improved methodology was used to assign values for concentrations
of 25 mononitro-PAHs and 3 dinitroyrene isomers in three diesel particulate-related
SRMs (SRM 1650a, SRM 1975, and SRM 2975) and two air particulate SRMs
(SRM 1649a and SRM 1648). Improved separation of PAHs isomers of MW
302 has resulted from the use of a 50% phenyl methylpolysiloxane phase
instead of the common 5% phenyl phase. GC/MS analysis of several environmental
matrix SRMs (air and diesel particulate matter, two sediments, and coal
tar) provided identification and reference values for 23 MW 302 isomers.
Both the nitro-PAH and the MW 302 PAH studies resulted in the most extensive
characterization of these groups of compounds in any environmental matrix
and have provided reference values for these SRMs.
Methods development for new emerging environmental pollutants has focused
on polybrominated diphenyl ethers (PBDEs), which are flame retardant
compounds commonly added to many plastics, resins and textiles, which
are then incorporated into products such as TVs, computers, furniture,
and carpets. Ten natural matrix SRMs have been analyzed for determination
of a suite of 26 PBDE congeners and the results will be used to assign
certified concentration values (see Technical Activity Report).
Environmental Specimen Banking and Marine Analytical Quality Assurance:
ACD has been involved in environmental specimen banking and marine analytical
quality assurance programs for over two decades; these activities are
collaborative efforts supported by both NIST resources and by funding
for the other federal agency partners (see below for Other Agency Activities).
ACD currently maintains the National Biomonitoring Specimen Bank (NBSB)
at two locations, the NIST Gaithersburg campus and the Hollings Marine
Laboratory (HML) in Charleston, SC. The NBSB is a cryogenic environmental
specimen bank that resulted from the pilot Environmental Specimen Bank
Program, which was established in 1979 with support from EPA, to develop
collection and banking protocols for human liver specimens and to cryogenically
store these specimens for retrospective contaminant analysis. Since
1982, the specimen bank has grown in number and types of specimens (e.g.,
sediments, fish tissues, mussels, oysters, human diet samples, marine
mammal tissues, and seabird eggs and feathers) collected as part of
several monitoring and research programs. The National Oceanic and Atmospheric
Administration (NOAA), Minerals Management Service (MMS), and the U.S.
Geological Survey (USGS) have been major consistent supporters since
the mid-1980's. A major expansion in environmental specimen banking
occurred in 1995 with an agreement between NOAA and NIST to establish
a marine environmental specimen bank (ESB) in Charleston, SC as part
of the Hollings Marine Laboratory (HML), a partnership with NOAA, two
institutions of higher learning and research (College of Charleston
and Medical University of South Carolina), and the South Carolina State
Department of Natural Resources. ACD currently has seven permanent staff
members, three postdoctoral research associates, and three graduate
students in the HML working on specimen banking and marine quality assurance
activities (see Technical Activity Report).
SRM Activities: During the past year, measurements have been
completed on a number of SRMs of importance to the clinical, environmental,
and food and nutritional communities; several important new SRMs are
described below:
· Clinical Reference Materials
- SRM 2921 Human Cardiac Troponin Complex (see Technical Activity Report).
After evaluation of six different candidate reference materials using
two round robin studies, the material was selected for SRM 2921. More
than 20 different commercial cTnI assays, made by 12 different manufacturers,
from the US, Europe, and Japan, were used to evaluate the candidate
materials. This choice was made after evaluation of the troponin material
for purity, stability, ability to provide harmonization of assay results,
and the commutability of the material among the 20 commercial cTnI assays
used in the study. SRM 2921 was issued in May 2004 as the first protein
health status marker SRM.
· Environmental Reference Materials
- SRM 1947, Lake Michigan Fish Tissue. SRM 1947 is a cryogenically homogenized
fish fillet prepared from adult lake trout (Salvelinus namaycush), which
will complement SRM 1946 Lake Superior Fish Tissue issued in 2003. SRM
1947 will have certified values assigned for trace elements (8), methylmercury,
PCB congeners (32), pesticides (15), and PBDE congeners (7) with reference
values assigned for 17 additional PCBs/pesticides/PBDEs and fatty acids.
This is the first tissue material with certified values for PBDE congeners.
SRM 2385 Contaminants in House Dust. House dust is a repository of
pesticides and other chemicals used indoors or tracked in from outdoors.
SRM 2585, Organic Contaminants in House Dust, will be issued in late
2004 with concentration values assigned for over 100 organic contaminants
including pesticides, PAHs, PCB congeners, and PBDE congeners.
SRM 1650b Diesel Particulate Matter. SRM 1650b is a reissue of the
original diesel particulate SRM issued in 1985. The recertified materials
have values assigned for over 80 PAHs and nitro-substituted PAHs.
· Botanical Dietary Supplement SRMs
- As part of the NIST/NIH/FDA collaboration to develop SRMs for use
in validating analytical methods for dietary supplements, we have prepared
a suite of ephedra-related SRMs (SRMs 3240-3244) including ground plant
material, two extracts, and two finished products (powdered oral dosage
form and protein powder). These materials have been value assigned for
ephedra alkaloids using a combination of LC-UV, CE, LC/MS, and LC/MS/MS
methods (see Technical Activity Report).
· Forensic SRMs - Three new SRMs
were developed in response to feedback from the forensic community as
to their most immediate needs for standards. The development of these
new SRMs was initiated with support from the NIST Office of Law Enforcement
Standards (OLES) and include: (1) an updated and redesigned SRM 1828b
Ethanol in Water for blood- and breath-alcohol testing (see Technical
Activity Report); (2) an SRM designed for qualitative arson analysis,
SRM 2285 Arson Test Mixture; and (3) an SRM for drugs of abuse in human
serum/blood is in progress to complement the current SRMs for drugs
of abuse in urine because forensic laboratories often receive blood
instead of urine for analysis.
The Organic Analytical Methods Group provides measurement quality support
to n a number of Other Federal Agencies including but not limited to:
- The National Institutes of Health (NIH),
- The U.S. Department of Justice (DoJ),
- The National Oceanic and Atmospheric Administration (NOAA),
- The Environmental Protection Agency (EPA),
- The Defense Threat Reduction Agency (DTRA),
- The Department of Defense (DoD),
- The Centers for Disease Control and Prevention (CDC).
Support for these activities accounts for approximately 30% of the
group budget.
Gas Metrology and Classical Methods
Research and measurement service activities within the Gas Metrology
and Classical Methods Group are focused on gas metrology, wet chemical
methods (gravimetry, titrimetry), coulometry, and maintenance of the
theoretical infrastructure for pH and conductivity measurements.
In the area of electrolytic conductivity we completed 5 SRMs; SRM 3190,
25 µS/cm, SRM 3191, 100 µS/cm; SRM 3192, 500 µS/cm;
SRM 3198, 5 µS/cm; and SRM 3199, 15 µS/cm. We also continued
our investigations of new standards packaging technology. The packaging
used in the past was not suitable for storage of electrolytic conductivity
solutions for more than one year. Each electrolytic conductivity solution
standard has to be remade every year and uncertainties cannot be lowered
below 1%. For the past three years all electrolytic conductivity solutions
greater than 500 µS/cm have been packaged in 50 ml glass ampoules.
In sealed ampoules the transpiration problem, which has plagued us in
the past, is solved and the solutions have multiyear self-lives. The
leaching problem is minimal since the solutions have high ion concentrations
already. This reduces the reissue rate for these high electrolytic conductivity
standards and allows us to devote more time to the development of low
electrolytic conductivity standards being requested by the pharmaceutical
industry to address new water purity specifications. However there is
no simple solution for the low electrolytic conductivity standards.
Leaching from glass is the limiting problem and will require some exotic
containers to solve. Until this issue is resolved, electrolytic conductivity
standards will continue to increase in price, and perhaps outstrip the
ability of our customers to pay. It is planned that the electrolytic
conductivity SRMs above and including 500 µS/cm will be discontinued
in favor of a written procedure. This written procedure is in the form
of a NIST SP-260 and implements an IUPAC standard, which describes the
production of electrolytic primary standards.
CCQM Pilot Study CCQM-P47 evaluated the performance of NMIs in the
measurement of electrolytic conductivity of two KCl solutions of nominal
conductivity equal to 50 mS/m (500 µS/cm) and 5 mS/m (50 µS/cm).
For the 5 mS/m solution, the pilot laboratory (NMi, Netherlands) discovered
a time-instability in the solution as stored in the bottles used for
distribution of the solution. Following discussion of the original results
among the participants in April 2004, the pilot laboratory, NMi (Netherlands),
decided to institute a time-dependent correction of the reference value.
For the 50 mS/m solution, the NIST result was initially higher than
the reference value. Following discussion at the CCQM Electrochemical
Analysis Working Group, April, 2004, the cell calibration procedure
used at NIST was modified to eliminate the non-IUPAC primary calibrants
that previously had been used. With this modification, the NIST result
for the 50 mS/m solution was in excellent agreement with the reference
value.
In the area of pH and pure materials we completed 4 SRMs; SRM 187e
Certification, Borate pH Buffer; SRM 999b, Potassium Chloride; SRM 915b,
Calcium carbonate; and SRM 350b, Benzoic Acid. These renewals restock
currently out-of-stock SRMs and were prepared with 5 years worth of
inventory.
Significant progress was made in our comparability with other NMIs
in pH. In the past a very small bias has been evident, along with a
larger uncertainty, when compared with other NMIs. Research has yielded
significant improvements in the Type A uncertainty ("scatter"),
associated with measurement replication, of the NIST pH SRMs. These
pH SRMs provide the primary benchmarks to establish the traceability
of pH measurements. The decreased uncertainty results from the elimination
of transient mixed potential phenomena within the Ag|AgCl electrodes,
used in the primary measurement, after they are transferred from the
storage solution (0.01 mol kg-1 HCl) to the pH SRM buffer being certified.
The mixed potential decays to a negligible level if the electrodes are
stored in the given buffer solution for at least 12 h prior to performing
the primary measurement. A corresponding pre-equilibration step was
incorporated into the NIST procedure for primary pH measurements. This
new protocol yielded a 3-fold improvement for the carbonate buffer (pH
10). Smaller improvements were noted for the phthalate buffer (pH 4).
Typical Type A uncertainties with the new protocol are less than 0.0005
pH for each buffer with overnight equilibration. This uncertainty now
equals or exceeds that of other NMIs that currently perform similar
measurements. A model, based on modern mixed-potential theory, was developed
and tested to explain the observed transient potentials at these Ag|AgCl
electrodes.
There were two international comparisons completed in 2004. CCQM Key
Comparison CCQM-K34 was designed to evaluate the agreement obtainable
for the assay of potassium hydrogen phthalate (KHP) using high-accuracy
assays. The seven participants each used coulometry. The NIST result
and its estimate of uncertainty agreed well with those of the other
"experienced" NMIs (who had participated in the corresponding
pilot study, CCQM-P36). In addition, the NIST estimate of uncertainty
was more complete than those submitted by all but one of the other participants
(one included the same set of sources), in that more possible sources
of uncertainty were included in the estimate.
SIM Pilot Study SIM.8.11P, piloted by CENAM, was a follow-up to the
previous SIM.8.P4, which had been piloted by NIST in 2000. Five participants,
including NIST, performed Harned cell pH methods (primary method). The
NIST results were in excellent agreement (within ±0.0017 pH)
with other experienced NMIs (those that had participated in previous
CCQM pH Key Comparisons CCQM-K9 or CCQM-K17). The NIST uncertainties,
which included all known Type A and Type B sources, were equal to or
smaller than those of the other participating NMIs in the primary measurement.
The reduction in the NIST combined uncertainty resulted from a threefold
reduction in the Type A uncertainty of the extrapolation of the acidity
function to obtain pa°, the acidity function in buffer without added
chloride (from which the pH in directly obtained). This reduction was
directly attributable to the implementation of pre-equilibration of
the Ag|AgCl electrodes used in the Harned cells. The results of this
Pilot Study correspond directly to the procedure for the certification
of the phosphate pH SRM 186g and support the validity of its certification.
The concentration of ozone (O3) in the atmosphere remains a significant
issue from both scientific and political perspectives. At tropospheric
levels, O3 is a health concern and contributes to global climate change
as a greenhouse gas, while stratospheric O3 protects earth from harmful
UV radiation. Since 1983, NIST has provided Standard Reference Photometers
(SRPs) based on UV photometry to ten US Environmental Protection Agency
(EPA) facilities to provide an infrastructure for the calibration and
traceability of ozone measurements within the US. More recently, the
international interest has prompted sixteen foreign laboratories to
acquire SRPs. Current efforts focus on further anchoring the SRP through
international comparisons, comparisons with NIST's primary nitric oxide
(NO) gravimetric standards and a nitrogen dioxide (NO2) permeation tube
system, and the development of an advanced primary reference standard.
Additionally, NIST and BIPM have been collaborating to transfer the
responsibility of international O3 measurement traceability to the BIPM.
Collaboration with the Process Measurements Division will continue in
the development of the next generation instrument for ozone determination.
The NIST SRP network continues to expand. Many more countries have
requested NIST SRPs for establishing traceability for their atmospheric
ozone measurements. New SRPs have been constructed and delivered to;
Hong Kong Environment Protection Department, Hong Kong S.A.R., China
(SRP34); National Institute for Environmental Studies, Tsukuba, Japan
(SRP 35); and U.S. EPA Region 9 Laboratory, San Francisco, CA (SRP 36).
In addition SRPs are regularly recertified against NIST SRP 2. Last
year we recertified; New South Wales Environment Protection Authority,
Sydney, Australia (SRP 21); Czech Hydrometeorological Institute, Prague,
Czech Republic (SRP 17); National Physical Laboratory, London, United
Kingdom (SRP 20); and U.S. EPA Radiation and Indoor Environments (SRP
7). In addition to the high level SRP work NIST does, NIST also offers
a calibration service for commercial ozone monitoring instrumentation.
This service is mostly offered to States and Federal Institutions, and
commercial instrument makers.
In the gas metrology area, NIST certified and issued 10 SRMs during
the past year; SRM 2629a, 20 µmol/mol NO in nitrogen; SRM 2737,
0.5 µmol/mol NO in nitrogen; SRM 2738, 1.00 µmol/mol NO
in nitrogen; SRM 2629a, 20 µmol/mol NO in nitrogen; SRM 1683B,
50 µmol/mol NO in nitrogen; SRM 1684B, 100 µmol/mol NO in
nitrogen; SRM 1693, 50 ppm Sulfur Dioxide; SRM 2731, 20 ppm Hydrogen
Sulfide; SRM 1677, 10 ppm Carbon Monoxide in Nitrogen; and SRM 1663,
1500 ppm Sulfur Dioxide.
We continue to support U.S. industry through development and dissemination
of high priority reference materials based on input from organizations
such as the American Industry Government Emissions Research (AIGER)
consortium and ASTM. Stakeholders in the AIGER group are working together
to facilitate the automobile industry meeting more stringent 2003 Federal
Tier II and California LEV II emission regulations. AIGER members include
the U.S.EPA, California Air Resources Board (CARB), General Motors,
Ford, and Daimler-Chrysler. In 1998, NIST worked with a Specialty Gas
contractor to blend two cylinders each of low NO standards at concentrations
of 0.5 µmol/mol, 0.75 µmol/mol, 0.95 µmol/mol, 1.05
µmol/mol and 1.25 µmol/mol. The ten new standards were prepared
employing a newly developed cylinder pretreatment, a NIST SRM 2629a
as the parent NO source and a diluent balance gas of specially gettered
nitrogen (O2 < 2 nmol/mol). The new standards have been analyzed
periodically against NIST dynamic permeation standards and have exhibited
excellent NO concentration stability for more than 4 years. In 2001,
AIGER provided direct funding to NIST's contractor to expedite the development
of two new NO SRMs at the lower concentrations of 0.5 µmol/mol
and 1.0 µmol/mol. NIST and its contractor used the same pretreatment
etcetera to blend forty cylinders of 0.5 µmol/mol and forty cylinders
of 1.0 µmol/mol NO in nitrogen candidate SRM mixtures. The ownership
of 27 candidate cylinders of each new SRM (54 total) was transferred
from AIGER to NIST; who certified twenty-five (25) stable cylinders
of NIST SRM 2737 (0.5 µmol/mol) and twenty-five (25) stable cylinders
of NIST SRM 2738 (1.0 µmol/mol). Additionally, thirteen cylinders
of each concentration were recently analyzed by NIST and returned to
AIGER members for their interim use - until the new SRMs become available
in early 2005.
We participated in four international gas mixture comparison studies
during FY04. In CCQM K-22, key comparison of volatile organic hydrocarbons,
it was shown that the six NMI participants generally agreed to with
2 %. In CCQM K-15 International comparison on global warming gases,
emission levels it was shown that the four participating NMIs agreed
to within 0.3% on the concentration of sulfur hexafluoride and carbon
tetraflouride. In CCQM K-26a, ambient levels of nitric oxide in nitrogen,
the agreement among the participant was well within 2 %. This comparison
is still undergoing active review and official results should be available
in April 2005. In the SIM region NIST piloted a study comparison on
automobile emissions (carbon dioxide, carbon monoxide, nitric oxide,
and propane). The results of this comparison, while improved over a
previous study, was still not of the levels expected from NMIs. It was
decided to repeat this comparison in FY2005. NIST is currently coordinating
a key comparison on hydrogen sulfide (CCQM-K41). This comparison will
run through FY2005 and a preliminary report will be available in Oct
2005.
NIST continued with the bilateral comparison program with the Netherlands
Measurement Institute (NMi). Gases compared this last year included,
sulfur dioxide, hydrogen sulfide, nitric oxide, and nitrogen dioxide.
Generally, all comparisons with NMi have shown agreement to within 0.5%
or better. The lone exception has been hydrogen sulfide, where a 2%
agreement has been demonstrated. While the comparisons with NMi will
continue, we will redirect our efforts into new gases needed by industry.
Our first interaction with new gases will be with ammonia, which is
needed by the automotive industry and the power industry. NIST expects
to develop capabilities in ammonia to support gas standards at the 1
to 500 µmol/mol level.
During the past two years, we have had discussions with EPA on traceability
of mercury measurements from coal-fired power plants. EPA is publishing
a regulation, which requires analysis of coal fired power plant emission
for mercury emission, and adherence to a maximum emission rate. This
regulation will go into effect over the coming years. EPA funded the
Gas Metrology team to establish a traceability link for mercury gas
standards. This work started in March 2003, with the deadline of December
2003 for traceable gas standards. Although NIST will not be able to
establish the ultimate traceability protocols by December 2003, NIST
delivered to EPA gas standards, which have been highly characterized
by NIST, with a provisional certified value in FY2004. In FY2005, EPA
again funded NIST to work on ways to better establish traceability,
methods for traceability for HgCl2, and to evaluate the stability of
the Hg gas standards. The ultimate traceable artifact for HgCL2 will
be based on generation HgCl2 from a dynamic generation system, which
will have traceable linkages to flow, mass, temperature, and pressure,
or through catalytic conversion of Hg gas standard.
The certified cylinder mixtures delivered to EPA are to be used in
their program to audit mercury monitoring sites to determine compliance
with regulations. Up till this point they had no way by which to provide
quality assurance for the audits. The program also provided data on
the performance of a mercury generation device and this data showed
that this device is a viable alternate option for calibration and audit
of mercury monitors.
The gas mixture NIST Traceable Reference Material (NTRM) program is
a procedure for producing and certifying traceable calibration gas standards.
Specialty Gas Companies produce, with concurrence from NIST, groups
of identical gas mixtures in cylinders, minimum of 10, analyze them
and send the data to NIST which then selects 10% of the group to be
sent to NIST for analysis. The group of cylinders is assigned one concentration
value and uncertainty by using the data generated by NIST for concentration
determination and the NIST and Producer data to determine the uncertainty.
These NTRM mixtures are under the prevue of the Producer, or Specialty
Gas Company, to be sold as traceable standards or to be used at the
Producer facilities to analyze other mixtures that are then sold as
traceable mixtures. In FY2004 three Specialty gas Companies produced
19 batches of NTRMs. The over 500 individual gas cylinders that comprised
these 19 NTRM batches will be used by the specialty gas industry to
produce approximately 50,000 NIST-traceable gas standards for end-users.
There have been requests, specifically from the automotive industry,
for NIST to provide NIST analyzed mixtures with lower uncertainties
than NTRMs. Lower uncertainties are needed to support the lower and
tighter restrictions on automobile emissions. A method of accomplishing
this is for NIST to analyze each NTRM mixture of a specific group and
provide a concentration and uncertainty for each specific cylinder;
these would be known as NTRM Prime (NTRM*). In this model the uncertainty
is lowered because NIST provides all the analytical data, and the batch
homogeneity is not considered. This new designation is available now
and new NTRM* batches are expected to be produced in FY2005.
One way to meet the increasing needs of industry for standards at much
lower concentrations is through dynamic dilution technology. Over the
past two years we have collaborated with the United Kingdom's National
Physical Laboratory (NPL) on the critical evaluation of a binary network
dilution device that they patented in 2001. This dilutor consists of
6 mass flow controllers (MFC) arraigned in series. Each MFC, or bit,
is adjusted to deliver precisely twice the flow of the preceding MFC.
Thus calibration consists of matching flows precisely, and does not
rely on absolute flow calibration. The binary network behaves like a
binary number, and dilution is easily adjusted through switching the
MFCs between the dilution gas and the standard gas. We have been working
to further develop this concept into a "primary" dilutor.
Work using Mol Bloc flow measurement technology and new state of the
art mass flow controllers, shows great promise for reducing the uncertainty
in the composition of gas mixtures delivered. This technology, and additional
dynamic dilution approaches will be utilized in a new dynamic dilution
facility to be developed at NIST in the gas metrology group over the
next two years. This dilution facility will require new investments
in instrumentation and research, but will allow NIST to produce gases
dynamically at low uncertainties. We hope to be able to produce primary
gases at an uncertainty approaching or bettering 0.1 % relatitive. If
we are successful we may be able to reduce our reliance on primary gas
standards in cylinders and be able to respond faster to needs for new
concentrations and new gases.
Molecular Spectrometry and Microfluidic Methods
The Molecular Spectrometry and Microfludic Methods Group conducts research
on the metrology of molecular spectrometry and develops standards for
calibration, validation, and performance of instruments for measuring
molecular spectra; conducts research on microfluidic devices, methods,
and applications for chemical analysis including studies of materials
and material properties affecting the flow of liquids in microchannels
and the use of microchannel and other electrophoretic methods for forensic
and toxicological applications and standards; has responsibility for
the development and certification of optical transmittance and wavelength
standards in the ultraviolet, visible, and near-infrared spectral regions,
of Raman intensity correction standards, and of fluorescence wavelength
and intensity standards; and works with users and manufacturers of analytical
instruments to assess and measure the performance of analytical methods
and to determine and address existing and future needs for analytical
instrument standards ranging from device calibration and instrument
performance through specifications for remote device control and data
interchange. Much of Group 839.04's FY 2004 activities are covered in
our Technical Activity Reports, the goal of this report is to document
other important activities carried out in FY 2004.
In FY04, 46 sets of solid absorbance filter SRMs were certified (16
sets SRM 930, 20 sets SRM 2031a, and 10 sets SRM 2930), and 221 optical
filter sets were recertified. Continuing measurements were made on a
number of other filter sets. Five-hundred seventy-six units of SRM 931g
Liquid Absorbance Filter were produced. Certificates were completed
for SRM 2037 (Solvent Red 24 Diesel Dye) and SRM 2243 (Relative Intensity
Standard for Raman Spectroscopy with 488 nm and 532 nm Excitation).
Initial measurements were made on SRM 2244 (Relative Intensity Standard
for Raman Spectroscopy with 1064 nm Excitation). Studies were carried
out on a material for a Relative Intensity Standard for Raman Spectroscopy
with 633 nm Excitation that may eventually become SRM 2245.
Certification was completed on SRM 293--an extended set of visible
filters (0.1%, 0.3%, and 70% transmittance) that enlarges the range
of transmittances covered by our visible optical filters and makes the
range of our visible filter offerings more compatible with those of
other NMIs (e.g., NPL) and meets requests by CORM, our NTRM vendors,
and others for broadening the range of our standards.
The report on using holmium oxide solution as an intrinsic standard
(one whose purity can be assessed inherently and whose wavelength "peak"
values at given spectral slit widths can be certified independently
and published as standard reference data) for UV/Visible wavelength
spectrometer calibration was completed and published. The wavelength
values were determined based on a holmium oxide wavelength intercomparison
with several NMIs around the world. Accordingly, it should no longer
be necessary for NIST to produce SRM 2034 (Holmium Oxide Solution Wavelength
Standard). This year's batch of 247 units of SRM 2034 should be our
last.
We continued our development of candidate materials for luminescence
standards. We developed a uranium-based glass and a manganese-bearing
glass that appear useable for fluorescence spectral emissivity standards
in the green and yellow spectral regions respectively. After several
difficulties in glass production, the glass bricks were sent off to
Optiglass in England for cutting and polishing. Candidate materials
for both blue- and violet-fluorescing emissivity standards are being
evaluated. We are having some problems due to the absorbance of the
base glass. We could go with the materials developed so far, but would
have to make a very large correction for the self-absorbance or "inner
filter" effects. Accordingly, we are looking for ways to fabricate
glasses of different matrices to avoid this problem. This is made difficult
because small amounts of platinum that dissolves from the crucibles
used in the glass making process are a principal cause of this absorbance
problem. We continue to search for a suitable candidate material can
be used as an emissivity standard the red.
We have nearly fully qualified our SPEX-JY fluorometer as a reference
instrument for making certified fluorescence measurements. We are now
getting reasonable agreement between the standard-detector and the standard-light-source
methods. We have developed a small light source for carrying out photobleaching
studies under controlled, reproducible conditions. In collaboration
with researchers at NIH, we have begun to construct a reference microarray
scanner that can be utilized for the certification of artifact standards
used for validating the performance of commercial microarray scanners.
We have organized and begun a study on the comparison of fluorescence
measurements involving five NMIs. The first steps compare relative emissivity
measurements on SRM 936 (Quinine Sulfate Dihydrate) and a set of dyes
covering the visible spectrum that were developed by BAM.
Three candidate materials for a new material supporting measurements
of high explosives (TNT, RDX, HMX), RM 8105 Trace Particulate Explosives,
were prepared, evaluated, and discussed at the major international meeting
focusing on explosives detection (ISADE). Additional candidate materials
are under development with the support of the Department of Homeland
Security.
The National Institute of Justice estimates a backlog of a 542,700
cases for DNA analysis as of April 2004, and current forensic crime
labs do not have the equipment capacity to address this backlog in a
timely manner. Forensic DNA analysis or "fingerprinting" involves
the measurement of the molecular size of several fragments of DNA produced
in a specially designed molecular-biological reaction. NIST's development
of a microfluidic device for forensic DNA analysis is addressing this
backlog by allowing for analysis techniques that are both faster and
more economical, while still ensuring the data created is of the highest
quality. Current microfluidic device designs fabricated and tested for
this purpose are approaching the desired performance for forensic analysis
in salient figures-of-merit to current state-of-the-art equipment with
the time required for analysis being reduced by nearly 90%.
The development of the initial Group Quality Manual QM-III-839.04 was
a major accomplishment this year. The initial version covers the production,
certification, and recertification of optical filter standards for absorbance
and the production and certification of Raman intensity correction standards.
Additions for the production and certification of the fluorescence standards,
standard Raman libraries, and the explosives standards will be added
as they are developed.
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