铬形态离子的毛细管电泳分离测定

Separation and Determination of Chromium(Ⅲ) and Chromium(Ⅵ) by Capillary Zone Electrophoresis

利用1,2-环己二胺四乙酸（CDTA）将Cr^3＋络合成络阴离子[CrC]^-，以甲酸盐为背景电解质溶液，毛细管区带电泳同时分析了[CrC]^-和CrO4^2-。重复性实验结果（n=9）：[CrC]^-和CrO4^2-的迁移时间相对标准偏差（RSD）分别为0．5％和0．8％，峰面积的RSD分别为4．6％和3．0％，峰高的RSD分别为2．5％和2．3％。当信噪比（S／N）为2时，CrO4^2-和[CrC]^-的检出限分别为0．3和0．08mg／L。峰面积对CrO4^2-及[CrC]^-质量浓度线性范围分别为0．625—20mg／L及0．15—10mg／L。相关系数分别为0．9986及0．9997。该分析方法简单实用。

Capillary zone electrophoresis （CZE） was applied to the separation and determination of chromium（Ⅵ） and chromium（Ⅲ） with formate as background electrolyte. Cr^3＋ was transformed into [CrC] - by using cyclohexane-1, 2-diaminetetraacetic acid（CDTA） as complexing reagent. The relative standard deviations of the determinations of migration times（ n = 9） for [ CrC ] - and Cr（ VI ） were 0. 5% and 0. 8% , respectively, and those of peak areas for [ CrC ] - and Cr（ Ⅵ ） were 4. 6 and 3.0, respectively. The detection limits for signal-to-noise ratio of 2 were 0. 08 mg/L for [ CrC ] - and 0. 3 mg/L for Cr（Ⅵ）. The linear ranges of peak area vs. concentration were 0. 15 - 10 mg/L with a correlation coefficient of 0. 999 7 and 0. 625 - 20 mg/L with a correlation coefficient of 0. 998 6 for [ CrC ] and Cr（ Ⅵ ）, respectively. The method is simple and feasible.