基于三唑磷残留限量值的多检测线免疫试纸条的制备与应用

摘要

A novel immunochromatographic assay was developed, which could provide visual evidence of triazophos in agro products, and also could directly identify the safety status by setting visual cut-off limit of detection in maximal residual limit ( MRL) value. Three test lines ( T1, T2, T3) were applied to the nitrocellulose membrane with different concentrations of Triazophos-OVA, and one control line (C) was settled with goat anti mouse IgG antibody. Thereafter, by combining with conjugate pad which immobilized monoclonal antibody labeled with 20 nm Colloidal gold particles, absorbent pad and PVC plate, a chromatographic test strip was assembled. With optimization of sample extraction and solvents selection, the test strips were employed for the determination of triazophos in rice, cabbage and apple. The results revealed that the cut-off limit of detection could reach 0. 005, 0. 01 and 0. 02 μg / mL represented by test line T3, T2 and T1, respectively. After modification, the cut-off limit of detection was resettled to 0. 05, 0. 1 and 0. 2 μg / mL according to the MRL values which enforced by the national standard of GB2763. Using acetonitrile for the sample extraction, the extracts were diluted 10 times or solvent exchanged with equivalent volume by PBS solution, and then tested by strips descripted above mentioned. The two test strips could precisely identified the safety status of agro product with MRL as threshold within 8-12 min. Furthermore, the residues value of triazophos could be quantified by the multiple quantitative test lines. Parallel GC data indicated that the strip had no false negative. This MRL-based multiple quantitative triazophos detection strip would provide a simple, direct, accurate and the most intuitionistic performance for the evaluation of agro product safety.%建立了基于三唑磷残留限量值(MRL)的免疫层析检测方法,可裸眼观察判断谷物、蔬菜和水果中的三唑磷农药残留水平.以粒径20 nm的胶体金标记三唑磷单克隆抗体于金标垫上,包被不同浓度的三唑磷包被原(检测线T1、T2、T3线)、羊抗小鼠IgG抗体(质控线C线)于硝酸纤维素(NC膜)上,与吸水垫及PVC底板组合成层析试纸条.以大米、甘蓝和苹果为对象,优化了样品前处理方法、提取试剂等条件.结果表明,基于1/10三唑磷MRL值的试纸条(I)对三唑磷的裸眼观察检测灵敏度可达0.005、0.01和0.02μg/mL,优化调整后获得试纸条Ⅱ灵敏度设定为国标GB2763中的三唑磷MRL值依次为0.05、0.1和0.2μg/mL,并与3条检测线一一对应.结合前处理方法优化结果,样品经乙腈提取后,用PBS稀释10倍或者等体积溶剂置换后检测,此两种试纸条在8～12 min内均可准确判定农产品中三唑磷的残留是否超过MRL值,同时多区间定量范围的设定亦可较为准确地定量其残留值,结果与GC方法一致.本研究采用基于MRL值的3条检测线,对检测结果的判定更为直接、准确,无需换算,为基于MRL农产品安全性的快速判断提供了更为直观、简单、准确的方法.