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Method Summary

Method Source Standard Methods
Method Number4500-B B
Revision InformationStandard Methods Online
Method NameDescriptive Name: Boron by Curcumin Method

Official Name: 4500-B B. Curcumin Method

MediaMedia: WATER
SubcategoryInorganic
Citation Standard Methods Online - Standard Methods for the Examination of Water and Wastewater
Method DownloadThis is a proprietary method.
Please visit the method owner's site for method documentation
Summary of MethodWhen a sample of water containing boron is acidified and evaporated in the presence of curcumin, a red-colored product called rosocyanine is formed. The rosocyanine is taken up in a suitable solvent and the red color is compared with standards visually or photometrically.
Scope and ApplicationThe curcumin method is applicable to determining boron in water in the 0.10 to 1.0 mg/L range. The range of this method can be extended by dilution or concentration of the sample.
Applicable Concentration Range0.10 to 1.0 mg/L (general); 0.05-0.2 mg/L (adapted)
InterferencesNitrate-N concentrations above 20 mg/L interfere. Significantly high results are possible when the total of calcium and magnesium hardness exceeds 100 mg/L as calcium carbonate. Moderate hardness levels also can cause a considerable percentage error in the low boron range. This interference springs from the insolubility of the hardness salts in 95% ethanol and consequent turbidity in the final solution.
QC RequirementsSee Section 4020 Quality Assurance/Quality Control.
Sample HandlingStore samples in polyethylene bottles or alkali-resistant, boron-free glassware. Preserve to pH <2 with nitric acid.
Max Holding Time6 months (regulatory) (See Section 1060)
Relative Cost/EffortLess than $50
Sample Prep Method(s) 
 

Method Boron by Curcumin Method has 1 analytes associated with it.

Analyte


Detection
Level

Bias Precision Pct False
Positive
Boron
(7440-42-8)		50 ug/L0 Rel. Error (ML)22.8 % RSD (ML)240 ug/L
export_analytes
Precision Descriptor NotesA synthetic sample containing 240 ug B/L, 40 ug As/L, 250 ug Be/L, 20 ug Se/L, and 6 ug V/L in distilled water was analyzed in 30 laboratories by the curcumin method with a relative standard deviation of 22.8% and a relative error of 0%.
Detection Level NoteThe Minimum Detectable Quantity of boron is 0.2 ug B. With water samples, the photometric method can be used to quantify boron levels to as low as 50 ug/L.
 
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