[Establishment of a rapid detection method of colloidal gold immunochromatographic competition assay for organophosphorus pesticides].

Objective To establish a colloidal gold immunochromatography and develop the corresponding test strip for detecting organophosphorus compounds including omethoate, phoxim, dipterex, and parathion in fruits, vegetables and drinking water. Methods Artificial antigen molecules of organophosphorus compounds were synthesized using N-hydroxysuccinimide esters. Acetylcholinesterase antigen was prepared and purified, and the serum containing the corresponding antibody was prepared, purified, and labeled. The working parameters of the test strip were optimized, and the performance evaluation of it was conducted. Results The titer of the antisera ranged from 1:32 to 1:64, with a protein content of approximately 2 mg/mL. The purified polyclonal antibodies displayed target bands at relative molecular masses (M) of 25 000 and 55 000, indicating satisfactory purity. The reaction time of the test strips was between 5 to 10 minutes, with a detection limit for samples at 200 ng/mL. Both specificity and accuracy were satisfactory, and the test strip remained valid for 6 months. Conclusion A simple and rapid colloidal gold immunochromatography is established successfully for detecting several organophosphorus compounds and may be useful for on-site preliminary screening of samples in large quantities.