The potential homogeneous assay employing immunomagnetic beads (IMB) has been receiving attention as a screening tool in food-safety control; the method is simple, efficient, and does not require long incubation times or complex separation steps. In this study, a homogeneous immunoassay has been successfully developed and applied in the determination of aflatoxin B1 (AFB1) contamination in agricultural products by coupling IMB and the biotin-streptavidin (BSA) (BSA-IMB) system. Under optimal conditions, the limit of detection (LOD, IC10), half-maximal inhibition concentration (IC50) and detection range (IC20-IC80) of BSA-IMB are 0.00579, 0.573 and 0.0183-17.9 ng mL-1, respectively, for AFB1. The detection of AFB1 by BSA-IMB can be achieved in 40 min (ELISA needs at least 180 min). The cross-reactivities of BSA-IMB with its analogues are negligible (<3.82%); these results indicate high selectivity. The spiked recoveries are in the range from 89.6 to 118.2% with relative standard deviations (RSDs) of 3.4 to 13.2% for AFB1 in agricultural product samples. Furthermore, the results of BSA-IMB for authentic samples show reliability and high correlation of 0.9928 with an HPLC-fluorescence detector. The proposed BSA-IMB system is demonstrated to be a satisfactory tool for homogeneous, efficient, sensitive, and alternative detection of AFB1 in a wide detection range for agricultural product samples.
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