时间分辨荧光免疫分析方法检测烟草中菌核净残留

建立了简便、灵敏地检测烟草中菌核净残留的时间分辨荧光免疫分析方法(TRFIA),及配套的无净化的快速前处理技术。采用镧系元素螯合物Eu-N1标记亲和纯化后的羊抗兔IgG示踪抗体。采用间接竞争TRFIA法建立了菌核净标准抑制曲线,方法的检出限I10为2.0μg/L;抑制终浓度I50为32.00μg/L;检测线性范围为4～128μg/L。考察了丙酮提取后33%,10%和1%的烟草基质对菌核净-TRFIA分析方法的影响,表明在1%烟叶基质条件下,建立的菌核净的抑制曲线的线性范围与标准抑制曲线趋于平行,确定烟草样品的前处理稀释倍数为100倍,计算得到基质影响因子(Im)为17.1。对烟叶样品中添加1,7和24mg/L的菌核净标样,连续3d的添加回收实验表明,方法的回收率为73%～128%,相对标准标准偏差(RSD)在4.3%～13.2%之间;烟草中菌核净的实际最低检出限为1mg/L。本方法可望用于烟草中菌核净残留的快速筛选检测。

Determination of Dimethachlon in Tobacco by Time-resolved Fluorescence Immunoassay

A sensitive time-resolved fluorescence immunoassay(TRFIA) with a cleanup-free pretreatment for dimethachlon in tobacco was developed.The competitive indirect TRFIA for dimethachlon was established by using goat anti-rabbit IgG conjugated with a Eu-N1clelate as a tracer.The detection limit(I 10) and I 50 for this assay was 1.98μg / L and 32.00μg / L,respectively.And the linear range for detection is between 3.97-128.76μg / L.Meanwhile,the effect of tobacco matrix to TRFIA was also studied.It was demonstrated that the linear range of inhibition curve with 1%tobacco matrix was parallel to the standard curve;so the extract of tobacco would be diluted 100times before assay,the index of matrix interference(I m) was calculated as 17.1.Three levels of dimethachon(1,7and 24mg / L) were spiked into tobacco,the overall recoveries and the relative standard deviations(RSDs) were in the range of 73%-128%and 4.3-13.2,and the practical detection limit for the method was 1mg / L.This assay is a suitable tool for screening dimethachlon residue in tobacco samples