氢化物发生辅助雾化火焰原子吸收法测定水中铅

Determination of Lead in Water Using Hydride Generation-assisted Flame Atomic Absorption Spectrometry

研究了一种提高火焰原子吸收测定铅灵敏度的新方法———氢化物发生辅助雾化的火焰原子吸收法;方法采用硼氢化钠与铅(Ⅳ)在原火焰原子吸收雾化器喷口处反应生成氢化物,以提高火焰原子吸收法的雾化效率;采用重铬酸钾-酒石酸预处理体系,重铬酸钾氧化样品中铅(Ⅱ)为铅(Ⅳ),酒石酸稳定铅(Ⅳ)的亚稳态化合物;对各种实验参数和干扰情况也进行了研究;方法操作简单、快速,灵敏度比通常的火焰原子吸收法提高了6.8倍;检出限(K＝3,n＝11)为6.64μg／L,线性范围为0.021～3.2mg／L;测定水样的回收率达94%～99%。

A hydride generation-assisted flame atomic absorption spectrometry for the determination of lead in water was developed.It is based on the lead hydride generated via the reaction of NaBH 4 and Pb(Ⅳ)at the nebulizer nozzle to improve the efficiency of nebulization.The potassiumdichromate-tartaric acid systemwas used for sample pretreatment.The former was used to oxidized the Pb(Ⅱ)to Pb(Ⅳ)while the latter to stabilized the Pb(Ⅳ)metastable compound.The determination parameters,such as flow rate of NaHB 4 ,concentration of NaHB 4 ,tartaric acid and potassium dichromate,and the oxidation time were optimized.The effects of the interˉfering ions on Pb absorbance were also studied.Compared with the conventional flame atomic absorption specˉtrometry,the sensitivity of Pb is improved by a factor of6.8.The linear range of determination of Pb is0.021～3.2mg/L and the detection limit(3σ)is6.64μg/L.The proposed method has been applied to the determination of Pb in several water samples with a recovery range of94%～99%.