Determination of aflatoxins in grains and raw peanuts by a rapid procedurewith fluorometric analysis

A rapid, quantitative, inexpensive, and efficient method was developed to d etermine aflatoxins in corn, corn meal, popcorn, rice, wheat, cottonseed, a nd peanuts. Samples are ground and extracted with methanol-water (80 + 20), A portion of the extract is cleaned up by passage through a solid-phase se paratory column, 500 mu L purified extract is derivatized with a bromine re agent, and fluorescence of the solution is immediately quantified with a ca librated fluorometer containing a broad wavelength pulsed xenon light sourc e. This method can quantify aflatoxin from 5 to 5000 ppb without dilution a nd was linear when applied to samples of noncontaminated corn spiked at 0 t o 5000 mu g aflatoxin B-1/g. Correlation coefficients of the method with LC for multiple analyses for corn (n = 34), cottonseed (n = 32), and peanuts (n = 11) were 0.999, 0.995, and 0.980, respectively. Individual analyses ma y be conducted in less than 5 min, and grouping of samples is unnecessary. The sensitivity of the method for corn is 5 ppb and the fluorometer, under the operating conditions, has a limit of detection of 0.6 ng aflatoxin B-1.