微分脉冲阳极溶出伏安法测定水处理剂用铝酸钙中砷

采用活性面位于侧面的金电极作为工作电极,建立了微分脉冲阳极溶出伏安法测定水处理剂用铝酸钙中砷含量的检测方法。将水处理剂用铝酸钙粉用氯化铝溶液加热回流溶解,经过滤后,对滤液进行稀释,以18%(质量分数)盐酸为支持电解质,对样品稀释液进行微分脉冲扫描阳极溶出伏安法测定。结果表明,砷在金电极上于峰电位为+0.09V左右产生灵敏的溶出峰,该峰峰高与砷的质量浓度在0.5~10μg/L之间呈现良好的线性关系,相关系数为0.997 7,检出限为0.15μg/L。按照实验方法对水处理剂用铝酸钙样品进行测定,并采用电感耦合等离子体质谱法(ICP-MS)做方法对照,同时加入砷标准溶液进行加标回收试验,结果表明,两种方法的测定结果基本一致,且实验方法的加标回收率为90%~102%。对3个水处理剂用铝酸钙样品测定结果的相对标准偏差(RSD,n=6)为2.1%~3.3%。

Determination of arsenic in calcium aluminate for water treatment agent by differential pulse anodic stripping voltammetry

The gold electrode with active surface at side was used as working electrode. The determination method of arsenic in calcium aluminate for water treatment agent by differential pulse anodic stripping voltammetry was established. The calcium aluminate powder for water treatment agent was dissolved in aluminum chloride solution by heating reflux. After filtration,the filtrate was diluted and determined by differential pulse anodic stripping voltammetry with 18% (mass fraction) hydrochloric acid as supporting electrolyte. The results showed that arsenic exhibited a sensitive stripping peak on gold electrode with peak potential about +0.09V. The height of this peak had good linearity to the mass concentration of arsenic in range of 0.5-10μg/L. The correlation coefficient was 0.9977. The detection limit of method was 0.15μg/L. The calcium aluminate sample for water treatment agent was determined according to the experimental method, and the standard solution of arsenic was added for recovery test. The results were were consist with those obtained by inductively coupled plasma mass spectrometry (ICP-MS). The recoveries of standard addition were between 90% and 102%. The relative standard deviations (RSD, n=6) of determination results of three calcium aluminate sample for water treatment agent were between 2.1% and 3.3%.