The method consists of methanol extraction, purification of the extract by transfer from aqueous methanol to chloroform, silica gel column chromatography, partition chromatography according to Pons on a celluloseaqueous methanol column, and quantitation by TLC fluorodensitometry. Average recoveries of B1, B2, G1, G2, and M1 from liver, kidney, heart, and round steak spiked at 0.05, 0.1, and 0.2 μg/kg were 43–123% as measured by TLC fluorodensitometry. The method was successfully applied to the analysis of naturally contaminated liver, kidney, and heart tissues.