Development of the Colloidal Gold Immunochromatographic Rapid Test Strip for the Determination of Diuron Residues
|School||Tianjin University of Science and Technology|
|Course||Nutrition and Food Hygiene|
|Keywords||Diuron colloidal gold immunochromatographic test strip|
In this paper, the colloidal gold immunochromatographic rapid test strip was developed for the determination of Diuron residues, which was effectively applied to identify trace Diuron in water sample.The Diuron competed with Diuron-BSA conjμgate immobilized on the strips to combine with the colloidal gold-labeled anti-Diuron polyclonal antibodies. Anti-Diuron polyclonal antibodies were purified by protein A-sepharose4B and KLH-sepharose4B. Gold chloride was reduced with sodium citrate and sodium borohydride to make17nm and6.56nm colloidal golds, which was coupled with the anti-Diuron polyclonal antibodies as immuno-colloidal gold after identification by transmission electronic microscope. The hapten-BSA and goat anti-rabbit IgG were dispensed on test line and control line respectively and the polyclonal antibody was solidified to glass fibers to prepare immunochromatographic strips. The detection method of indirect competition was established:gold-labeled antibodies were combanied competitively by Diuron and Diuron-BSA coated with solid phase carrier film. Diuron residue levels in samples can be rapidly determined by observation. The coated antigen, dilution fold of the gold-labeled antibodies and the Goat anti-rabbit antibody were standed at0.24μg,1:2and1:500as the optimum conditions, respectively.The limit of detection of Diuron test strip was5ng/mL. The established method was validated by the instrumental method of HPLC. Fifteen water samples, determined to be free of the analyte, were spiked at three concentrations of5,20,100ng/mL. After filtered by0.22μm membrane, the samples were directly used for analysis by HPLC. The results obtained by test strip were coherence with the results obtained by HPLC. The results indicated that the test strips can be applied in the rapid detection of Diuron residues.The interference with the detection of Diuron residues caused by the structural analogue compounds was studied. When the concentration of Chlorbromuron, Linuron, Thidiazron, Monuron, and Monolinuron was1000ng/mL, the effect of cross-reactivity could be ignored, which validated the specificity of the test.The process of detection is simple, rapid and convenient, which could be finished within10minutes. The results can be visually read by eyes without instrumentation. The stability and simplicity make it feasible to determine the large number of water samples.