Radioimmunoassay of aflatoxins: technique of determination, interfering compounds

Radioimmunoassay of aflatoxins can be performed by a number of various techniques. One well-proven method of determination uses the 125I-radioligand, separation with activated carbon, long-term incubation (12 hrs) at a temperature of 5 degC in the medium of a phosphate buffer (pH=7.5, 0.05 M) with an addition of casein. The range of the calibration curve is between 0.02 and 0.6 pmol of aflatoxin in a 0.1 ml sample. The specific binding used is 30 to 40%, the non-specific binding is 8 to 12%. Reproducibility expressed as % of the variation coefficient of repeat determinations was 20.2%, 13.4% and 16.3% for low, medium and high concentrations of aflatoxin, respectively. The possibility was confirmed that bovine and human serum may interfere with the determination, but not lactalbumin. (author)