B. S. Liao, T. T. Cain, PRL/SW, FDA, Irvine, CA
Background:
A method has been developed to separate and quantify putrescine, cadaverine, and histamine simultaneously for scombroid fish samples and fishery products by cation ion chromatography. This method is an alternative to the two official methods currently used to analyze for these three biogenic amines. Putrescine and cadaverine are analyzed by Gas Chromatography (AOAC Method 996.07) and histamine is analyzed by Fluorescence Spectroscopy (AOAC Method 977.13). This method eliminates the need for chemical derivatization and the sample preparation is quick and simple.
Methods:
Aqueous 5mM sulfuric acid mobile phase is used with a cation exchange column under isocratic condition at a flow rate 0.8 mL/min and a run time of 30 minutes. Fish samples are homogenized with 75% methanol/water, incubated at 60ºC for 15 minutes and filtered before injection.
Results:
The three biogenic amines are baseline separated regardless of scombroid fish matrix in the order of putrescine, cadaverine, and histamine, without the interferences traditionally seen for tuna with cation ion chromatography. Five different scombroid fish samples, tuna, mackerel, anchovy, mahi mahi and sardines, were spiked in duplicate with standard solutions of the three amines with recoveries within 80% - 120%. The correlation coefficients (r2) of the standard calibration curves for putrescine, cadaverine and histamine are all higher than 0.999. The lowest standard concentrations which were spiked into tuna fish matrix are 0.055 ppm for putrescine, 0.05 ppm for cadaverine, and 1.0 ppm for histamine with RSDs of 1.5%, 5.4%, and 4.7%, respectively.
Conclusion:
This method is simple, direct, effective, and is also environmentally friendly because no chemical derivatization or time-consuming sample preparation is necessary.