析相微萃取-火焰原子吸收光谱法测定水样中痕量铅

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1.07～96 μg/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0.63 μg/L。对铅浓度为20.0 μg/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。

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

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 μg/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 obtained by inductively coupled plasma atomic emission spectrometry with relative standard deviations(RSDs，n=7) of 4.1%-5.8% and recoveries of 95%-98%.