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要测定水中ppb数量级的砷,氢化物的发生可作为一种富集分离手段。通常海水中砷的平均浓度是3ppb左右,而且海水中存在有大量的常见元素,对微量元素的测定常发生干扰。若采用ICP-AES法测定时,这种干扰就会大大减小,截止目前,尚未见到采用ICP-AES法直接测定海水中砷的方法。我们设计了双管同时进样的封闭式反应装置,用NaBH_4还原可溶性的亚砷酸盐,生成砷化氢(AsH_3),作为ICP-AES法测定海水中超痕量砷的预先分离手段。本文对一些物理和化学条件进行了最佳化试验选择,获得砷的检出限为0.2ppb,定量测定下限为1ppb,回收率为82—106%,变异系数≤±15%。
To determine the level of ppb in water arsenic, hydride generation can be used as a means of enrichment and separation. Usually, the average concentration of arsenic in seawater is about 3 ppb, and there are a large number of common elements in seawater, which often interfere with the determination of trace elements. If the ICP-AES method is used, the interference will be greatly reduced. Up to now, there is no method to directly determine arsenic in seawater by ICP-AES. We designed a two-tube simultaneous injection of closed reaction device, NaBH_4 reduction of soluble arsenite to generate hydrogen arsenide (AsH_3), as ICP-AES method for the determination of ultra-trace amounts of arsenic in seawater before the separation means. In this paper, some physical and chemical conditions were optimized test selection, the detection limit of arsenic was 0.2ppb, the lower limit of quantitation was 1ppb, the recovery rate was 82-106%, the coefficient of variation ≤ ± 15%.