Determination of arsenic in foods by flow injection on-line sorption pre-concentration with hydride generation atomic fluorescence spectrometry

Abstract

A method was developed for the determination of total arsenic in foods using flow injection on-line sorption coupled with hydride generation atomic fluorescence spectrometry (HG-AFS) using a cigarette filter as the sorbent material. After reducing As(V) to As(III) by using L-cysteine, the determination of total arsenic was achieved through on-line formation and retention of the pyrrolidine dithiocarbamate arsenic complex (As(III)–PDC) on the cigarette filter, which was packed in the pre-concentration column and total arsenic was determined by HG-AFS. The analytes were eluted with 1.68 mol l⁻¹ HCl from the sorbent material. With consumption of 22 ml of the sample solution, an enrichment factor of 25.6 was obtained at a sample throughput of 11.6 h⁻¹. The detection limits (3 standard deviations) and the precision (relative standard deviation) in foods ranged from 2.5 to 9.9 ng g⁻¹ and from 1.1 to 2.2%, respectively. The method was used to determine arsenic in carrot, mushroom, chicken tissue, cod fish, rice, common carp and shrimp.

Keywords:

• arsenic
• hydride generation atomic fluorescence spectrometry (HG-AFS)
• cigarette filter
• flow injection
• foods

Acknowledgements

The authors are grateful for financial support from the Science and Technology Development Foundation of Tianjin Colleges and Universities (Project No. 2006ZD19) and the Ministry of Science and Technology of the People's Republic of China (Project No. 2006BAD05A06).