Improved liquid chromatographic method for determination of aflatoxins in peanut butter and other commodities

A combination of the extraction and cleanup procedures of Pons and Franz with the liquid chromatographic (LC) derivatization technique of Beebe is proposed as an accurate, precise, and sensitive method for determination of aflatoxins B1, B2, G1, and G2 in various foodstuffs. Mean recoveries of total aflatoxins added in the range 15-34 ng/g to peanut butter were 86-94% in 2 laboratories. Recovery of total aflatoxins (30 ng/g) from shelled peanuts, shelled Brazil nuts, pistachios, cashews, walnuts, and filberts exceeded 86% and from pumpkin seeds was 80%. Coefficients of variation for total aflatoxins were less than 7% for spiked samples and 15% for peanuts naturally contaminated with 16.7 ng/g of total aflatoxin (B1 + B2). Analyses of peanut meal, yellow corn meal, and peanut butter check samples (AOCS Smalley Series 1980/81 and 1981/82, IARC Series 1982/83) by this method compared favorably with reported averages. The detection limit is about 0.3 ng/g for each aflatoxin.