微分脉冲溶出伏安法结合化学计量学测定醚类除草剂

Simultaneous Determination of Two Herbicides by Differential Pulse Stripping Voltammetry and Chemometrics

在pH=6.82的Britton-Robinson缓冲溶液中,采用循环伏安法和微分脉冲溶出伏安法对醚类除草剂甲羧除草醚（Bifenox）和三氟羧草醚（Acifluofen）的伏安行为进行了研究,发现吸附时间为50 s时此电化学体系达到平衡,而且微分脉冲溶出伏安法能给出较高的灵敏度,甲羧除草醚和三氟羧草醚分别在-685 mV和-700 mV处具有良好还原峰,但由于峰电位接近而谱峰重叠,很难分别测定。本文采用化学计量学方法来解析重叠峰并完成这两种除草剂的定量分析。甲羧除草醚和三氟羧草醚的测定线性范围分别为0.02-0.18μg.mL^-1和0.02-0.16μg.mL^-1,检出限分别为0.0073μg.mL^-1和0.0068μg.mL^-1。利用该方法对水样中的甲羧除草醚和三氟羧草醚进行直接测定,获得了较好的定量分析结果。

A differential pulse stripping voltammetric method（DPSV） was developed for the simultaneous determination of bifenox and acifluofen at a hanging mercury drop electrode（HMDE） with the aid of chemometrics.The voltammograms of these two compounds overlapped seriously,and generally it was difficult to determine them individually from their mixtures.Therefore,chemometrics approaches,such as classical least squares（CLS）,principal component regression（PCR） and partial least squares（PLS）,were used in this study to resolve the overlapped voltammogram and determine each herbicide in mixtures. A set of mixtures of these two compounds was prepared and used to verify the established chemometrics models. The results showed that the calibration models with the data collected at pH 6.82 had better prediction as compared with other pH values, and both PLS and PCR gave lower prediction errors than CLS. The proposed method has been applied to the analysis of two target herbicides in waters with satisfactory results.