摘要
建立了应用流动注射在线共沉淀分离富集火焰原子吸收法测定天然水样中痕量铬的价态分析方法。利用铬（Ⅲ）在碱性条件下与氢氧化镧形成共沉淀而与共存离子分离并得到富集，沉淀不需过滤，直接用稀盐酸从编织反应器（ＫＲ）中溶解并洗脱下来，用原子吸收测定。本体系的浓集倍率２２，检出限（３σ）０．８μｇ／Ｌ，相对标准偏差（ｎ＝１１）２．７２％，用水标样考察，分析结果与推荐值相符。该方法成功地用于天然水中铬的快速测定。
A flow injection on-line Coprecipitation-FAAS system for the determination of Cr(Ⅲ) and Cr(Ⅵ) was developed. The analyte was preconcentrated and separated from the coexitting elements by on-line Coprecipitation with Lanthanum hydroxide. The precipitate was collected on the wall of the knotted reactor without filter, then dissolved on-line by 0.5 mol/L HCl at a flow rate of 6 mL/min and introduced into the nebulizer burner system of FAAS. A Concentration efficiency of 22 and a detection Limit (3σ) of 0.8 μg/L were achieved. The relative standard deviation (n=11) was 2.72%. The analytical results obtained for natural water samples were in good agreement with the certified values. The method has been applied success fully to determinate the trace amount of Cr(Ⅲ) and Cr(Ⅵ) in natural water samples.
关键词
流动注射
共沉淀
铬
价态分析
天然水
Flow Injection, on-line coprecipitation, chromium speciation, knotted reactor
