Quantification of aflatoxins B1, B2, G1, and G2 in pepper by HPLC/fluorescence

Sample cleanup with Sep-Pak cartridges and validation of an HPLC/fluorescence method for separation and identification of aflatoxins in pepper was carried out. The samples were extracted with chloroform/water and filtered. The filtrate was purified on a silica cartridge followed by a C-18 cartridge. Aflatoxins were derivatized with trifluoracetic acid and analyzed by HPLC with a column containing TSK gel ODS 80 TM CTR. Validation of the method was evaluated by recovery studies and CV%. Samples of black and white pepper were spiked in triplicate with total aflatoxins B-1, B-2, G(1), and G(2) at 3, 6, and 12 mug/kg levels. Recovery values were in the range of 86.2-96.2 for aflatoxin B-1, 91.2-97.7 for aflatoxin B-2, 85.3-94.2 for allatoxin G(1), and 89.8-97 for allatoxin G(2) with CV% being less than 12.1%. The detection limits for each aflatoxin, based on a signal-to-noise ratio of 3, were 0.009 mugL(-1) for G, and 0.006 mugL(-1) for B-1, G(2), and B-2. Twenty-two samples of pepper (4 black and 18 white) were analyzed for aflatoxins by high performance liquid chromatography with fluorescence detection. The degree of contamination in a lot of white pepper imported from India (six samples) and in sixteen samples randomly purchased from the market was estimated. Fourteen of the analyzed samples contained aflatoxins (B-1, B-2, G(1), or G(2)); however, they were below the limit of 20 ppb fixed by the European Union, except for one.