A Monoclonal Antibody-Based Immunoassay for Mepanipyrim Residue Sensitive Analysis in Grape Juice and Wine

Mepanipyrim is a new-generation anilinopyrimidine pesticide that is employed nowadays to fight fungal diseases in a variety of crops. Rapid and user-friendly analytical methods that can complement the instrumental techniques are demanded. To analyse residues of this toxic compound in foodstuffs, monoclonal antibodies were generated for the first time, and an enzyme-linked immunosorbent assay was developed. In the present study, a series of haptens mimicking the mepanipyrim molecule, and with a linker at alternative sites of the molecular framework, were designed and prepared by total synthesis in order to study the influence of the linker tethering site over the binding properties of the generated antibodies. This strategy afforded high-affinity and specific monoclonal antibodies to mepanipyrim. Interestingly, the highest sensitivity was reached with antibodies that had been raised using haptens with the spacer arm at the most characteristic moiety of the analyte, the 1-propynyl group. Moreover, the influence of the triple bond was investigated both in immunizing bioconjugates and in assay antigens. Finally, a competitive enzyme-linked immunosorbent assay was optimized and characterized, showing an IC50 value of 0.3 mu g/L for mepanipyrim. Good accuracy and precision values were found when grape juice and wine samples were analysed.