Comparison of four thin-layer chromatographic methods for the determination of aflatoxins in raisins

A study was conducted to determine the accuracy and precision of 3 AOAC methods, secs 26.026-26.031 (CB), secs 26.032-26.036 (BF), and secs 26.052-26.060 (cottonseed), and the Romer quantitative method for the thin-layer chromatographic (TLC) determination of aflatoxins B1, B2, G1, and G2 in raisins. The samples were spiked at a level of 10 micrograms total aflatoxins/kg. The TLC development systems were: ether-methanol-water (94 + 4.5 + 1.5) and chloroform-acetone (9 + 1). The interaction between the 4 methods and the 2 development systems was also studied. The average recoveries were 88, 80, 75, and 93% with coefficients of variation of 14.0, 10.4, 14.0, and 9.6% for aflatoxin B1 using the CB, BF, cottonseed, and Romer methods, respectively. Statistical analysis showed no difference in the results obtained using the 2 TLC development systems.