Development of a highly sensitive biotin-streptavidin enzyme-linked immunosorbent assay for detecting diethyl phthalate based on a specific polyclonal antibody

An indirect competitive biotin-streptavidin enzyme-linked immunosorbent assay (BA-ELISA) has been established for the determination of diethyl phthalate (DEP) in wine samples. A highly sensitive and specific polyclonal antibody (pAb-DEP) targeting DEP was prepared. Under optimized conditions, good linearity was achieved within a range of 0.021-9.512 mu g center dot L-1. The limit of detection (IC10) was 0.0079 mu g center dot L-1 and the median inhibitory concentration (IC50) was 0.443 mu g center dot L-1. Besides, the BA-ELISA was highly selective, with low cross-reactivity values with DEP analogs (below 5%). Finally, the concentrations of DEP in wine samples ranged from 5.93 mu g center dot L-1 to 59.15 mu g center dot L-1 by BA-ELISA. Satisfactory recoveries (89.19-112.33%) and variation coefficient values (5.81-9.43%) were successfully obtained. The consistency between the results of BA-ELISA and gas chromatography-mass spectrometry (GC-MS) was 97.48%, which further confirmed that the proposed BA-ELISA immunoassay is reliable, rapid, sensitive, and accurate for monitoring DEP in wine samples.