Development Of Rapid Immunoassay Methods For The Determination Of Triazine Herbicide Prometryn

In this paper, a direct competitive enzyme-linked immunosorbent assay (dc-ELISA) and a colloidal gold immunochromatographic assay (CGIA) for rapid detection of prometryn were developed.Polyclonal antibodies with high titer and specificity were obtained from rabbits immunised with hapten-BSA. The working conditions for ELISA (antibody incubation concentration, enzyme tracer dilution, the type and concentration of blocking solution, etc.) were optimized, and the chemical effects factors on assay (ionic strength, pH values) were studied. The best results were obtained when antibody incubation concentration was0.25μg/well, blocking solution was0.5%skim milk, the dilution of the enzyme tracer was1:50000, and the assay buffer was1×PBS, pH7.4. The optimized ELISA presented a sensitivity (IC50) of0.3±0.03ng/mL, with a detection limit (IC15) of0.04±0.006ng/mL. The cross-reactivities (%) with other triazine herbicides were all low, except for propazine (71.4%) and prometon (50%). The Haihe river water, soil and rice were chosen as samples. The average recoveries of prometryn in these samples ranged from80%to120%, and the limit of detection is0.4ng/mL,0.8μg/kg and0.8μg/kg, respectively.17.4nm of colloidal gold particles were prepared via trisodium citrate method. The CGIA conditions were optimized for high sensitivity.The dilution fold of the coating antigen, the gold-labeled antibody and the secondary antibody were1:15,1:10, and1:300, respectively. The NC membrane didn’t require any treatment, while the conjugate pad was blocked with10%sucrose,5%BSA,0.1%tween, and0.1%NaN3. The detection limit of CGIA was5ng/mL and the detection process could be completed within5min. Haihe river water samples were detected directly by the strip and the limit of detection was5ng/mLThe accuracy of the developed methods was validated by the high-performance liquid chromatography (HPLC). The correlation between the data obtained using the ELISA and HPLC was high (R2=0.986). A good agreement was also observed between the data obtained using the CGIA and HPLC. Therefore, the developed immunoassays in this study were suitable for the rapid determination of prometryn in environmental and food samples.