Efficiency of different extraction solvent mixtures used in analyses of aflatoxins from a certified peanut meal reference material

Four analytical methods with different extraction solvent mixtures were used to compare the efficiency of the extraction step in the analysis of aflatoxins from a reference material with a certified value of 206 +/- 13 mug aflatoxin B-1 kg(-1). The extraction mixtures used were chloroform-water (100 + 10), acetonitrile water (60 + 40), acetone-water (85 + 15) and methanol-water (80 + 20). The analytical values determined from the extraction mixtures after correction for recovery were 211, 204, 163 and 120 mug kg(-1), respectively. The small amounts of aflatoxin B-2 in the reference material followed the same pattern. The selection of extraction solvent mixture is very important for achieving the true value and that correction for recovery does not always fully compensate for getting the correct analytical value.