Analytical Sciences

A Simple and Sensitive Flow-Injection On-line Preconcentration Coupled with Hydride Generation Atomic Fluorescence Spectrometry for the Determination of Ultra-trace Lead in Water, Wine, and Rice

Hong WU,*^,** Yan JIN,* Mingbiao LUO,*** and Shuping BI*

*School of Chemistry and Chemical Engineering, Key Laboratory of MOE for Life Science & State Key Laboratory of Coordination Chemistry, Analytical Center, Nanjing University, Nanjing 210093, China
**Department of Chemistry, Xuzhou Normal University, Xuzhou 221116, China
***Department of Applied Chemistry, East China Institute of Technology, Jiangxi 344000, China

A simple and sensitive flow-injection on-line separation and preconcentration system coupled to hydride generation atomic fluorescence spectrometry (HG-AFS) was developed for ultra-trace lead determination in water, wine, and rice samples, with the salient advantages of its minimization of transition-metal interferences and tolerance to an ethanol matrix. A lead hydroxide precipitate was achieved by the on-line merging of a sample and an ammonium buffer solution and collected onto the inner walls of a knotted reactor (KR). Removal of the residual solution from KR was achieved by air flow, and dissolution of the precipitate was carried out by using 0.2 mol l^-1 HCl. With a sample consumption of 11.7 ml, an enhancement factor of 16 was obtained at a sample throughput of 30 h^-1. The limit of detection (3s) was 16 ng l^-1 and the precision (RSD) for 1.0 µg l^-1 Pb was 3.4%.

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