流动注射在线分离富集-火焰原子吸收光谱法测定环境水样中Cr(Ⅲ)和Cr(Ⅵ)的形态

采用单阀阴离子和阳离子交换树脂微柱并联 ,两柱交替采样逆向洗脱流动注射在线分离富集环境水样中Cr(Ⅲ )和Cr(Ⅵ ) ,分别用 15 %HNO3和 8%NH4 NO3洗脱 ,火焰原子吸收光谱法直接检测。富集 1min时Cr(Ⅲ )和Cr(Ⅵ )的特征浓度分别为 :1 5 0 μg·L- 1 和 1 39μg·L- 1 ,Cr(Ⅲ )和Cr(Ⅵ )检出限 (3σ)分别为 1 0 3μg·L- 1 和 0 5 4 μg·L- 1 ;相对标准偏差 (10 μg·L- 1 )分别为 :3 4 1%和 1 80 % ,分析样品加标回收率在 93 5 %～ 10 7 5 %之间。

Determination of Chromium(Ⅲ) and Chromium(Ⅵ) in Water Using Flow Injection On-line Preconcentration and Separation with Flame Absorption Spectrometric Detection

A rapid and sensitive method for the sequential determination of Cr(III) and Cr(VI) in water samples based on flow injection on-line preconcentration and separation with two-microcolumn system-flame atomic absorption spectrometry has been developed. The Cr(III) and Cr(VI) in water samples were respectively retained in a microcolum with cation exchange resin and in a microcolumn with anion exchange resin and were eluted directly by 15% HNO3 and 8% NH4NO3, respectively. The characteristic concentrations (pre-concentration time of 1 min) for Cr(III) and Cr(VI) were 1.50 micrograms.L-1 and 1.39 micrograms.L-1, respectively, The relative standard deviations at 10 micrograms.L-1 level were 3.41% and 1.80%, and the corresponding detection limits (3 sigma) were 1.03 micrograms.L-1 and 0.54 microgram.L-1, respectively. The satisfactory recovery of 93.48%-107.5% could be obtained from water samples.