石墨炉原子吸收光谱法测定环境水中的铬(Ⅲ)与铬(Ⅵ)

Determination of Cr(Ⅲ)and Cr(Ⅵ)in environmental Water by Graphite Furnace Atomic Absorption Spectroscopy

在环境科学的研究中,铬是一个重要项目。用石墨炉原子吸收法测定环境及人体中的铬(Ⅲ)与铬(Ⅵ)已有报导。本文拟定了在水样中加入硝酸镁为基体改进剂,直接测定总铬;另取样品在pH4.5的醋酸盐缓冲液中以APDC-MIBK萃取测定铬(Ⅵ)的方法,并以差减法求铬(Ⅲ)。

Magnesium nitrate is used as matrix modifier for direct determination of total chromium in water.Cr(Ⅵ)is extracted by APDC-MIBK in another aliquot at pH 4.5 and determined in the organic phase.The amounts of Cr(Ⅲ)is obtained by subtracting Cr(Ⅵ)from total Cr.The instrumental parameters,radiation sources,background,arids and acidity,matrix modifiers and effects of foreign elements were studied.The detection limit of total Cr and Cr(Ⅵ)were 0.71 and 0.69μg/L respectively.The recovery of Cr is between 92.5-114%and the RSD%of Cr is 7.61-24.74 at different concentration levels.