基于编结反应器,提出了流动注射-氢化物发生-原子荧光光谱法测定水中痕量镉含量的方法.样品与氨水-氯化铵缓冲溶液在线混合,产生的沉淀收集到编结反应器内壁,引入空气除去编结反应器内残留的溶液,泵入盐酸(3+97)溶液溶解沉淀,与硼氢化钾合并后用原子荧光光谱仪测定.在优化的试验条件下,当样品消耗15.6 mL时,富集倍数为14倍,方法检出限(3S/N)为2.9 ng·L-1,相对标准偏差(n=11)为3.4%.方法用于国家标准物质和天然水样中痕量镉的测定,测定值与标准值相符,天然水样的回收率在91.5%~107.5%之间.

FI-HG-AFS by using knotted reactors (KR) was applied to the determination of trace amount of cadmium in natural water.The sample was on-line mixed with ammonia(aq.)-ammonium chloride buffer solution,and the precipitate of cadmium was collected on the inner walls of the knotted reactor.The removal of the residual solution from KR was achieved by introduction of air flow,and the precipitate was dissolved by HCl (3+97) solution.The solution obtained was mixed with KBH4 solution and used for HG-AFS detection.Under the optimal experimental conditions,an enrichment factor of 14 was obtained with sample consumption of 15.6 mL.The detection limit (3S/N)of the method found was 2.9 ng·L-1 and RSD (n=11) found was 3.4%.The proposed method was used for analysis of standard reference materials and natural water samples,the results of determination obtained was in agreement with the standard values,and values of recovery of Cd in natural water samples were ranged from 91.5% to 107.5%.