Production and characterisation of polyclonal antibodies to the common moiety of some organophosphorus pesticides and development of a generic type ELISA

Most of the commonly used organophosphorus (OP) pesticides share a similar moiety in chemical structures. We used this moiety [(CH3O)2‐P(S)‐O‐] to synthesise a ‘generic‐OP’ hapten, which was linked through a 4‐carbon spacer to bovine serum albumin (BSA), against which polyclonal antibodies (PAb) were raised. Other analogues of the generic‐OP hapten were also prepared with varying lengths of spacer group and used in an inhibition ELISA, developed for PAb characterisation. Greater inhibitions of the PAb were recorded with Fenitrothion, Methacrifos, Propetamphos and Dichlorvos with 50% inhibition values of 4.8, 8.2, 36.2 and 91.1 μg ml−1 respectively. Compared to these OPs, in which phosphorus is linked to specific side groups via an oxy‐ester link, other compounds either with a thio‐ester link or in which side group contains a pyridine or pyrimidine ring, showed much lower inhibition. Using analogues of the generic‐OP hapten as inhibitors, the greatest inhibitions of the PAb were recorded with hapten containing a 4‐carbon spacer group, and progressively lower inhibitions with a decrease in length of spacer. However, some inhibition of the PAb was noted for the generic—OP analogue with a single carbon side group. The information gained from these studies will be useful in the design of immunogens for other small molecule haptens, and production and use of generic PAb against a group of chemically‐similar compounds.