Hapten synthesis, generation of polyclonal antibodies and development of ELISA for determination of thiamethoxam residues in food and environmental samples

Abstract

An ELISA (enzyme-linked immunosorbent assay) method for the determination of thiamethoxam residues has been developed. The method involves the synthesis of hapten and generation of polyclonal antibodies in rabbit using the hapten-protein (bovine serum albumin) conjugate carrier. Recovery experiments show the accuracy of estimation of thiamethoxam residues that was within the linear working range of 1 to 60 ng mL⁻¹ with the r²=0.992. Influence of different parameters, like detergent concentration, solvent, pH, ionic strength, has been studied. Cross reactivity was tested using different analogs. The method tolerates the solvent methanol concentration up to 15%. However, other polar solvents influence negatively on the binding. The detergent Tween 20 has not made any impact on the absorbance. The optimized ELISA for thiamethoxam used 1-60 ng/well and an antiserum dilution between 10000 and 200000. Recoveries were above 98%. The method was successfully applied for the analysis of food and environmental samples.