Polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for screening of paclobutrazol in fruits

Paclobutrazol (PBZ) is a plant growth regulator (PGR) widely used in fruit and vegetable cultivation. However, due to the severe toxicity of PBZ, a sub-ppm level maximum residue limit (MRL) was established worldwide. Therefore, it is significant to propose a rapid, sensitive and high throughput screening method for monitoring the PBZ residues in foods. In this study, a simple and sensitive indirect competitive Enzyme-linked immunosorbent assay (icELISA) was established for PBZ detection in fruits basing polyclonal antibody. For both economy and pollution prevention, a microwave-solvent-free method was used to synthesize the PBZ hapten with high efficiency. The detection conditions, such as coating antigen concentration, antibody concentration, organic reagent concentration, ionic strength and pH, were optimized. Under the optimized conditions, this method showed high sensitivity and specificity. The detection range is 1.27-138.23 ng/mL, half-maximum inhibition concentration (IC