荧光法检测辛硫磷残留量及其分析应用

Determination of Phoxim Residues by Fluorescence Spectrometry and its Analytical Application

在pH为6.00的Britton-Robinson缓冲溶液中,水溶性荧光素（SF）与一定浓度的溴化十六烷基三甲基铵（CTMAB）反应,使其荧光强度剧增,当在SF-CTMAB中加入辛硫磷（phoxim）后,体系的荧光强度明显降低,且降低程度与辛硫磷的加入量呈良好的线性关系,据此建立了测定辛硫磷残留量的新方法.在优化实验条件下,线性范围为0.032-0.72 mg·L^-1,检出限为0.026 mg·L^-1,已用于大米和土壤中辛硫磷残留量的检测,回收率在97.5%-100.5%之间,相对标准偏差为1.3%-2.2%,符合农药残留分析的要求.

In the Britton-Robinson buffer solution at pH 6.20, the fluorescence intensity of soluble fluorescein （SF） is enhanced violently with a certain concentration of the eetyl trimethyl ammonium bromide（CTMAB） present. The enhanced fluorescence intensity is declined obviously after adding phoxim and the reduced fluorescence intensity is proportional to the concentration of phoxim. Based on this, a new fast and simple method for determination of the phoxim residues has been developed. Under optimal conditions, the linear range of this assay is 0. 032-0.72 mg/L and the detection limit is 0. 026 mg/L. The method has been successfully applied to the determination of the phoxim residues in rice and soil, the average recoveries of the method range from 97.5% -100.5% with a relative standard deviation （RSD） range of 1.3%-2.2%. It is suggested that this method is in line with the request of pesticide residue analysis.