A SIMPLE SOLID‐PHASE RADIOIMMUNOASSAY FOR AFLATOXIN B₁

Abstract

A solid‐phase radioimmunoassay (RIA) for aflatoxin B1 (afla B1) was developed. This method involved the incubation of afla B1, both labelled and unlabelled, with immunoglobulin (IgG)‐sepharose gel which was prepared by conjugation of the IgG highly specific to afla B1 with CNBr‐activated sepharose gel, followed by a filtration step. The binding capacity was determined by counting the radioactivity in the filtrate. Studies with different afla B1 analogues revealed that the IgG‐gel bound most effectively with B1. Binding of afla B2, G1, G2, and aflatoxicol to the IgG‐gel was less effective in comparison with the IgG before coupling. Between 0.5–5.0 ng per assay, the displacement of radioactivity from the gel was directly proportional to the amount of afla B1 present. Using a simple extraction procedure without clean‐up step, the recovery yields for afla B1 in the contaminated corn or wheat at levels of 5 ppb or above were above 60%.

Production and Characterization of Antibody Against Aflatoxin G1

“…Recent investigations in our laboratory and others (Chu 1984a;1984b) have developed a radioimmunoassay (RIA) (Chu and Ueno 1977;Langone and 'Present Address: Hybritech Inc., San Diego, CA 92121 Journal of Food Safety 7 (1985) 161-1 70. All Rights Reserved @Copyright 1985 by Food & Nutrition Press, Znc., Westport, Connecticut Van Vunakis 1976;Sizaret et al 1980;Sun and Chu 1977) and an enzyme linked-immunosorbent assay (ELISA) (Biermann and Terplan 1980;Pestka et al 1980) for analysis of aflatoxins B1, B2a, and M1 in corn, peanuts, wheat and milk (El-Nakib et aL 1981; Fremy and Chu 1984;Pestka et al 1981). Although these methods are very simple, sensitive and specific, the antibodies used in these analyses are very specific for B types of aflatoxins; thus they can not be used for AFGl analysis (Chu and Ueno 1971;Guar et aL 1981;Harder and Chu 1979;Langone and Van Vunakis 1976;Sizaret et al 1980).…”

Production and Characterization of Antibody Against Sterigmatocystin

“…Generally, thin-layer chromatography (TLC) has been used for the analysis of ST in foods or feeds (Vorster and Purchase 1968;Shannon and Shotwell 1976;Athnasios and Kuhn 1977;Van Egmond et al 1980 (Stack et al 1976;Schmidt et al 1981). However, both TLC and HPLC methods are very time consuming and also lack specificity In view of our recent success in the development of radioimmunoassay and enzyme linked immunosorbent assay (ELISA) for a number of mycotoxins (Chu and Ueno 1977;Harder and Chu 1979;Sun and Chu 1977;Pestka etal. 19801, attempts to develop specific antibody against ST were undertaken.…”

The occurrence of aflatoxins in peanuts imported into Czechoslovakia for human consumption

“…For rapid screening of aflatoxins, immunochemical methods have been developed (Sun andChu 1977, Píchová et al 1981). We have used radioimmunoassay (RIA) for determination of aflatoxins in peanuts imported into Czechoslovakia.…”