Aflatoxin estimation in corn by measurement of bright greenish-yellow fluorescence in aqueous extracts

A procedure was developed for efficient extraction of bright greenish-yellow (BGY) fluorescent material from ground corn ( Zea mays L.) samples and subsequent quantitative determination of fluorescence emission in a fluorometer. The technique was designed to be inexpensive, rapid and utilizable at remote locations for estimation of aflatoxin levels. A simple, in vitro method for production of the BGY-fluorescing material from kojic acid was developed to provide a reference standard. Water was identified as an effective solvent for extraction of the BGY-fluorescence from corn; fluorescence in aqueous extracts was stable at pH 6-7 for up to 22 h at room temperature. Samples with aflatoxin concentrations of 0 to 12,000 ppb yielded BGY-fluorescence emission units of 0 to 175. A correlation coefficient of r = 0.77 was determined for BGY-fluorescence vs total aflatoxin levels (B , B , G , G ) and r = 0.88 for the fluorescence vs aflatoxin B , B . The results provided a basis for effective determination of BGY-fluorescence as an estimate of aflatoxin levels in corn.