Matrix Interference of Vegetable on Enzyme-Linked Immunosorbent Assay for Parathion Residue Detection

Complex matrix of vegetable severely interferes with enzyme-linked immunosorbent assay (ELISA) accuracy, limiting its application in parathion residue detection. This study investigated the interference mechanism of vegetable matrix, including chlorophyll, perilla protein, glucose, fructose, and sucrose, on ELISA. Furthermore, we validated the vegetable matrix interference on parathion residue ELISA by comparing the matrix interference index (Im) and recovery rate of vegetable samples before and after acetic acid-treatment. The results demonstrate that the addition of vegetable matrix significantly interferes with ELISA, with the antibody–IgG-HRP binding being subject to the most pronounced interference. Compared to the Im (16–26%) of non-acetic acid treatment, the Im (10–13%) was significantly reduced after the acetic acid treatment. Concomitantly, spiked recovery experiments of acid-treated samples yielded satisfactory average recovery rate (80–113%) as the matrix interference was minimized. The findings of this study provide valuable insights into the mechanism of vegetable matrix interference on ELISA.