高效液相色谱-原子荧光光谱法分析底泥孔隙水中形态砷

Analysis of Arsenic Forms in Interstitial Water of Sediment by High Performance Liquid Chromatography-Atomic Fluorescence Spectrometry

砷是我国实施排放总量控制的指标之一,不同形态砷的毒性差别较大,因此研究砷的形态具有重要的意义.当前形态砷的研究主要集中在水产品方面,而对底泥孔隙水中形态砷研究较少.底泥孔隙水中砷的形态及污染情况是重要的环境指标,可影响生活于其中的生物并间接影响人类健康.采用高效液相色谱-原子荧光光谱法,以磷酸氢二铵为流动相,盐酸为载流,硼氢化钾为还原剂,对流动相的pH、光电倍增管负高压、空心阴极灯电流、盐酸体积分数、硼氢化钾浓度等参数进行了优化.在优化的测试条件下,亚砷酸盐[As(Ⅲ)]、二甲基砷(DMA)、一甲基砷(MMA)和砷酸盐[As(Ⅴ)]4种砷的形态在5~100μg/L范围内线性关系良好,标准曲线线性相关系数均大于0.9991,4种形态砷的检出限在0.22~0.43μg/L之间,相对标准偏差(RSD)均小于4.0%,各组分的加标回收率在89.0%~103.0%之间.测试结果表明方法准确可靠、操作简单,可用于底泥孔隙水中形态砷的测定.

Arsenic is one of the indicators for the total emission control in China. The toxicity of different forms of arsenic varies greatly. Therefore, the study of arsenic forms is of great significance. The current research on arsenic forms mainly focused on the aquatic products, while the study on arsenic forms in the interstitial water of sediment is few. Arsenic forms and pollution in sediment pore water are important environmental indicators, which can affect the living organisms and indirectly affect the human health. High performance liquid chromatography-atomic fluorescence spectrometry(HPLC-AFS) was used, with diammonium hydrogen phosphate as the mobile phase, hydrochloric acid as the carrier current and potassium borohydride as the reducing agent. Under optimized test conditions, arsenite [As(Ⅲ)], dimethyl arsenic(DMA), monomethyl arsenic(MMA) and arsenate [As(Ⅴ)] were determined. The linear correlation coefficients of standard curves were greater than 0.999 1. The detection limits of four arsenic forms were 0.22~0.43 μg/L. The relative standard deviations(RSDs) were less than 4.0%, and the recoveries of each component were 89.0%~103.0%. The results showed that the method is accurate, reliable and easy to operate, and can be used for the determination of arsenic speciation forms in the interstitial water of sediment.