萃取分离-石墨炉原子吸收法测定铬(Ⅲ)与铬(Ⅵ)

Determination of Chromium(Ⅲ) and Chromium(Ⅳ) by Extraction Separation-Graphite Furnace Atomic Absorption Spectrometer

本文介绍了以APDC-M IBK萃取体系分离铬(Ⅲ)与铬(Ⅵ),在pH=2.0的条件下铬(Ⅲ)与APDC反应,再被萃取入M IBK中。而铬(Ⅵ)在氢离子浓度为2mol/L的条件下直接萃取进入M IBK中,再用石墨炉原子吸收分光光度计分别测定。分析方法的线性范围为4-48ng/m l,标准曲线的相关系数r=0.9998。检出限分别为铬(Ⅲ)=0.8ng/m l,铬(Ⅵ)=0.7ng/m l。批间及批内精密度均小于5%。钠、铅、锌、钙等离子在4.0mg/l00m l时均不引起干扰。该法具有灵敏度高,准确度高,特异性好、精密度好等特点。

Chromium （ Ⅲ ） and （ Ⅳ） were separated by APDC - MIBK extraction separation method. Under the condition of pH was 2.0, Chromium （Ⅲ） reacted with APDC, and then it was extracted into MIBK. But Chromium （ Ⅳ ） would be extracted into MIBK directly under the condition of [ H ^＋ ] was 2 mol/L, and then it could be determined by graphite furnace atomic absorption spectrometer. The linear range of this analysis method was between 4ng/ml to 48ng/ml, the correlation coefficient （r） of standard curve was 0. 9998. The detection limits of Chromium （ Ⅲ ） and （ Ⅳ） were 0.8ng/ ml and 0.7ng/ml respectively. The reproducibility was less than 5%. Na ^＋ , Pb^2 ＋ , Zn^2 ＋ , Ca^2 ＋ would not interfere when their concentrations were 4. 0mg/100ml. This method was high sensitivity, accuracy, precision and good specificity.