微分脉冲溶出伏安-偏最小二乘法同时测定代森锌和代森锰

采用循环伏安法讨论了两种常用的杀菌剂代森锰和代森锌在汞电极上的电化学还原反应机理,发现它们均具有良好的的伏安还原峰.采用微分脉冲溶出伏安法研究本体系时,获得的代森锰和代森锌的线性范围分别为0.005～0.07 mg/L和0.02～0.24 mg/L;检出限分别为4.10和12.8μg/L.由于这两种杀菌剂的分子结构很相似,它们的伏安波谱峰重叠严重,采用常规方法很难对它们分别进行测定.为解决波谱重叠的问题,本研究采用主成分回归和偏最小二乘法对波谱进行解析.结果表明,偏最小二乘法能得到较好的定量结果.利用本方法对几种蔬菜和水果样品进行分析,三氯甲烷作萃取剂的萃取率最大,回收率在95.5％～103％之间.

Simultaneous Determination of Zineb and Maneb by Differential Pulse Stripping Voltammetry and Partial Least Squares Method

A differential pulse stripping voltammetric method(DPSV) was proposed for the determination of zineb and maneb at a hanging mercury drop electrode(HMDE).The voltammagrams of these compounds seriously overlapped,and it is difficult to determine these two compounds individually from their mixtures.Quantitative analysis for each of the fungicide compounds in a mixture was investigated with the aid of principal component regression(PCR) and partial least squares(PLS).A set of synthetic mixtures of the compounds was analyzed by using the proposed methods,and it was found that the lowest relative prediction error(RPE) was achieved with the PLS procedure.The proposed method was also applied to several vegetable samples spiked with known amounts of the fungicides with satisfactory results.