无载体离子有机共沉淀分离-石墨炉原子吸收光谱法测定海水中铜铅铬镍

Determination of copper,lead,chromium and nickel in seawater by carrier element-free coprecipitation combined with graphite furnace atomic absorption spectrometry

以吡咯烷二硫代氨基甲酸铵(APDC)氧化物作为共沉淀剂,建立了无载体离子有机共沉淀分离、石墨炉原子吸收光谱法测定海水中铜、铅、铬、镍的方法。考察了海水样品pH、共沉淀剂APDC和氧化剂H_2O_2的用量、陈化时间等因素对共沉淀分离效果的影响,优化了实验条件。结果证明,在p H4~5的海水样品中,加入4 m L 30 g/L APDC,1 m L H_2O_2,静置60 min,待测元素能与海水基体很好的分离。铜和铬含量在0~20μg/L范围内呈良好的线性关系,线性相关系数R>0.999;镍含量在0~30μg/L,铅含量在0~40μg/L范围内呈良好的线性关系,线性相关系数R>0.998;检出限分别为0.31,0.30,0.20,0.25μg/L,方法精密度好,加标回收率为88.8%~101.4%。方法可用于海水样品中铅、铜、镍、铬的常规检测。

A method was developed for the determination of copper （Cu）, lead （Pb）, chromium （Cr） and nickel （Ni） in seawater samples by graphite furnace atomic absorption spectrometry after ammonium pyrrolidine dithiocarbamate （APDC） coprecipitation without carrier element. Effects of some analytical parameters including seawater sample pH value, the amount of coprecipitant APDC and oxidant H2 O2, standing time on the presented coprecipitation system were investigated. The results showed that the analytic elements were separated well from the seawater matrix in the pH range of 4 5 with 4 mL 30 g/L APDC and 1 mL H2O2 after 60 min standing time. The calibration curves for Cu and Cr were linear in the range of 0 - 20 μg/L, and the linear correlation coefficients （R） were higher than 0. 999. The calibration curves exhibited linear relationship between the absorbance and concentration of Ni and Pb in the range of 0 - 30 μg/L and 0 - 40 μg/L, respectively, with correlation coefficients（R） higher than 0.998. The detection limits were found to be 0. 31, 0.30, 0.20 and 0. 25 μg/L for Cu, Cr Ni and Pb, respectively, and the recoveries for the target elements were 88.8% - 101.4%. The method could be applied to the determination of Cr, Cu, Ni and Pb in seawater samples.