用三正辛胺-苯萃取分离体系-原子吸收光谱对铬作形态分析

研究了痕量铬形态分析的三正辛胺(TOA)-苯萃取分离体系-原子吸收光谱法。用三正辛胺(TOA) 和苯在H2SO4介质中把水相中的Cr(Ⅵ)萃入到有机相而Cr(Ⅲ)留在水相中,使两种形态的Cr分离到两相 中后对有机相的Cr(Ⅵ)和水相的Cr(Ⅲ)进行AAS测定,可求得Cr(Ⅵ)和Cr(Ⅲ)的含量,该方法对实际水 样加标回收率分别在95．0％-102％和94．8％-103％之间,相对标准偏差分别为2．9％和2．6％,体系对 Cr(Ⅵ)有富集作用,对Cr(Ⅵ)和Cr(Ⅲ)的检出限分别为6．6μg·L-1和0．20 mg·L-1,TOA对Cr(Ⅵ)的最佳 萃取量为4．6 mg·mL-1,该法简单、快速、准确。

Speciation Analysis of Chromium(Ⅵ) and Chromium(Ⅲ) in Water Sample Using Flame Atomic Absorption Spectrometry with TOA-Benzene Extraction Separation System

A rapid and sensitive method for the sequential determination of Cr(VI) and Cr(III) in water samples based on flame atomic absorption spectrometry with TOA-benzene extraction separation system has been developed. In the H2SO4 medium. Cr(VI) in sample solution was extracted into the organic phase by using the TOA-Benzene and Cr(III) remained in the water phase. Cr(VI) in the organic phase and Cr(III) in the water phase were determined separately by AAS. This method is simple, fast and of microscale. The results obtained by this method agreed well with those obtained by conventional method. The recoveries are 95.0%-102% for Cr(VI) and 94.8-103% for Cr(III). The relative standard deviations were 2.9% for Cr(VI) and 2.6% for Cr(Ill). The system has enrichment effect for Cr(VI), and the detection limits are 6.6 microg x L(-1) for Cr(VI) and 0.20 mg x L(-1) for Cr(III). The maximum extracted amount of Cr(VI) by TOA was 4.6 mg x mL(-1).