纳米二氧化锆微柱分离电感耦合等离子-质谱分析水样中铬的形态

Nanometer-Sized ZrO_2 Microcolumn Separation Combined with ICP-MS for the Speciation of Chromium in Water Samples

以纳米ZrO2为微柱填充材料,采用电感耦合等离子-质谱(ICP-MS)研究了Cr(Ⅵ)/Cr(Ⅲ)在纳米ZrO2微柱上的吸附性能。当pH值为8时,纳米ZrO2能完全吸附Cr(Ⅲ),而对Cr(Ⅵ)基本不吸附。对影响Cr(Ⅵ)和Cr(Ⅲ)分离的主要因素进行了详细研究,据此建立了纳米ZrO2微柱分离ICP-MS分析铬形态的新方法。方法对铬的检出限(3σ)为0.06ng/mL,定量测定下限(10σ)为0.37ng/mL,相对标准偏差为2.2%(n=9,c=100ng/mL)。本法选择性好、简便、快速,已用于不同水样中铬形态的测定,结果满意。

A simple and convenient method has been developed for the speciation of Cr（Ⅲ） and Cr（Ⅵ） in water samples by nanometer-sized ZrO2 microcolumn separation and ICP-MS detection. The adsorption behaviors of Cr（Ⅲ） and Cr（Ⅵ） on nanometer-sized ZrO2 were studied and it was found that at pH=8.0 Cr（Ⅲ） could be quantitatively adsorbed by the microcolumn and Cr（Ⅵ） passed through the microcolumn directly. The main factors affecting the separation of Cr（Ⅲ） and Cr（Ⅵ） on nanometer-sized ZrO2 were studied. Under the optimal conditions,the relative standard deviation for chromium was 2.2%（c=100 ng/mL,n=9）,the limit of detection（3σ）was 0.06 ng/mL and the limit of determination （10σ） was 0.37 ng/mL. No obvious interference has been observed from the co-existed species. The proposed method has been successfully applied to the speciation of chromium in real water samples.