粮食中百草枯残留的金标免疫层析检测方法研究

Study on Gold Labeled Strip for Detection of Paraquat Residues in Food by Immune Chromatography

采用柠檬酸三钠还原法制备胶体金,研究胶体金与抗体蛋白的作用过程,确定稳定标记1.0 mL胶体金需8.10μg抗体蛋白,标记体系的最佳pH值为8.5。以金标抗体为分析探针,PQ-h-OVA为竞争抗原,羊抗兔IgG为控制抗体,构建直接竞争胶体金标免疫层析检测体系(GICA)。确定膜上包被抗原的质量浓度为0.50 g/L,点样量为1.0μL/条;金标点样量:5.0μL/条;羊抗兔二抗的最佳包被质量浓度为0.11 g/L,点样量为1.0μL/条。金标试纸条的目测检出限为10μg/L,检测时间约5 min,交叉反应率小于0.10%。方法的重复性和稳定性较好,该试纸条在室温下至少可保存5个月。

The colloidal gold was prepared with sodium citrate as reducing agent,and the study of the interaction between the colloidal gold and protein was investigated.The optimum parameters were obtained by using 8.10 μg antibody protein for 1 mL colloidal gold in pH 8.5.A direct competitive colloidal gold immune chromatographic assay（GICA）was constructed by using the colloidal gold antibody as analysis probe,PQ-h-OVA as competitive antigen and goat anti-rabbit IgG as control antibody.The optimum concentration of coating antigen was 0.50 g/L,the antigen and the gold colloidal sol were 1.0 μL per strip and 5.0 μL per strip,respectively,and mass concentration of the anti-antibody（IgG） was 1.0 μL per strip（0.11 g/L）.The lowest detectable amount was found to be 10 μg/L and the detection time was within 5 min.The cross reactivity was less than 0.10%.The method showed good repeatibility and stability,and the test strips could be preserved in 5 months.