The aim of this work is to provide a rapid

selective and very high sensitive method for the determination of aflatoxins B1(AFB1) using the indirect competitive time-resolved fluoroimmunoassay (TRFIA). On the indirect competitive assay

aflatoxins B1-horseradish peroxidase (AFB1-HRP) is bound on the surface of a microtiter plate. AFB1 containing samples or standards and a rabbit anti- AFB1 antibody are given in the wells of the microtiter plate. Solid-phase bound and free AFB1 compete for the antibody binding sites

the secondary antibody

labelled with Eu3+ is used to enable detection. The luminescent enhancement solution contained mainly 2-naphthoyltrifluoroacetone. Results showed the AFB1 detection limit to be 0.01 μg /L for indirect competitive TRFIA formats. The 80%

50%

20% inhibition binding effect dose (ED80

ED50

ED20) of AFB1 were (0.07±0.01) μg/L

(0.63±0.02) μg/L and (12.5±0.47) μg/L

respectively. The assay range was 0.01—100 μg /L. The cross reactivity with aflatoxins B2 was 10% and antibodies did not react with aflatoxins G2

ochratoxin A

ochratoxin B and HRP. The within-run and be- tween-run CVs of the AFB1- TRFIA were 4.1% and 6.8%

respectively. The mean recoveries of samples were 97.2%. Both TRFIA and ELISA tests were applied to the quantitative measurement of AFB1 in the same samples

and the co- efficient of correlation was 0.917. The present studies clearly show that the newly developed TRFIA could be applied to detect the AFB1 contamination in samples. The AFB1-TRFIA provides very high sensitivity and optimal range

and it will be useful to screen AFB1 contamination easily

simply and economically when the number of samples is large.