电化学发光免疫分析方法检测蔬菜中噻虫啉的含量

Detection of Thiacloprid in Vegetables by Electrochemiluminescence Immunomethod

化学农药的广泛使用,不可避免的产生了农药残留问题.蔬菜作为人类食物之一,其农药残留问题尤其重要.本文采用饱和硫酸铵盐析法提纯噻虫啉,并合成了Cd S纳米晶,制备了具有稳定且强电致化学发光的Cd S纳米晶膜,在纳米晶膜上建立了农药残留物噻虫啉含量的电化学发光免疫检测方法.该方法利用具有优良导电性的石墨烯作为抗原标记物,实现了噻虫啉的灵敏检测.标记上石墨烯的噻虫啉与纳米晶膜表面的抗体免疫结合后引起纳米晶膜发光的增强,发光强度的增加随着噻虫啉的含量的增加而增大.发光强度的对数与噻虫啉浓度的对数在0.1~10 pg·m L-1范围内呈线性关系（R=0.99）.在S/N比为3时,检测限为0.1 pg·m L-1.利用该方法检测实际蔬菜样品中的农药残留量,取得了令人满意的结果.鉴于石墨烯良好的可修饰性,其作为标记物在其他免疫反应、DNA杂化分析中具有十分广阔的前景.

The problem of the pesticide residue results from a wide use of chemical pesticides.It is of great importance to deal with the problem of pesticide residues in vegetables.In this paper,an electrochemiluminescence immunoassay method was established to detect the thiacloprid content of pesticide residues.This method used Cd S nanocrystals（NCs） and graphene as ECL emitters and antigen Label respectively.When thiacloprid（the antigen）labeled with graphene was bound to antibody on the Cd S NCs film through the formation of immunocomplex,ECL emission from Cd S NCs film was greatly enhanced.The ECL increment（ΔI） increased with the concentration of thiacloprid.The logarithm of the concentration of thiacloprid is linearly related to the logarithm of ECL increment within the range of 0.1 ~ 10 pg.m L-1（R = 0.99）.At a S/N ratio of 3,the detection limit was 0.1 pg.m L-1.Satisfactory results were obtained when this method was applied to the detection of pesticide residues in real samples.Graphene,easily being modified,has a very broad prospect as a label to be used in other immunoassay as well as in DNA hybridization analysis.