析相微萃取-火焰原子吸收光谱法测定水样中痕量铅

Determination of trace lead in water samples by microsphere phase extraction-flame atomic absorption spectrometry

铅离子与1-(2-吡啶偶氮)-2-萘酚(PAN)反应生成疏水性的络合物,在助溶剂丙酮的作用下被萃取到四氯化碳相中,用火焰原子吸收光谱法测定四氯化碳相中的铅,建立了析相微萃取-火焰原子吸收光谱法测定水样中痕量铅的分析方法。对影响络合反应和相分离的各种条件进行了优化。在最佳实验条件下,铅的质量浓度在1.07～96μg/L范围内与吸光度呈线性关系,相关系数为0.998 3,方法的检出限为0.63μg/L。对铅浓度为20.0μg/L的样品溶液进行7次平行测定,相对标准偏差为3.7%。该方法用于水样中铅的测定,测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)相吻合,相对标准偏差(RSD,n=7)为4.1%～5.8%,回收率在95%与98%之间。

After reaction with 1-（2-pyridylazo）-2-naphthol （PAN） to form a hydrophobic complex and extraction into carbon tetrachloride phase with the existence of cosolvent acetone, lead in the carbon tetrachloride was determined by flame atomic absorption spectrometry, Finally, a microsphere phase separation extraction-flame atomic absorption spectrometry was developed for determination of lead in water samples. Various conditions affecting complex reaction and phase separation were optimized. Under the optimal experimental conditions, there was a linear relationship between absorbance and lead concentration in the range of 1.07-96 μg/L with the correlation coefficient of 0. 998 3. Detection limit of this method was 0.63 μg/L. The relative standard deviation was 3.7% by determination of sample solution which contained 20.0 12g/L Pb for seven times. This method had been applied to the determination of lead in water samples. It was found that the results were consistent with those ob- tained by inductively coupled plasma atomic emission spectrometry with relative standard deviations （RSDs,n=7） of 4.1%-5.8% and recoveries of 95%-98%.