Determination of thallium(III) with novel arsenoxylphenylazo rhodanine after pre-concentration and separation

Abstract

A new catalytic kinetic fluorescent method for determination of trace thallium(III) was investigated. The method was based on the catalytic effect of thallium on oxidation of 3-p-chlorophenyl-5-(2′-arsenoxylphenylazo) rhodanine (4ClRAAP) by hydrogen peroxide in potassium hydrogen phthalate-hydrochloric acid (pH = 5.2). Under the optimum conditions the great increase of fluorescence intensity had a linear relationship against the concentration of thallium in the range of 0.43 to 10.0 µg L⁻¹ with a detection limit of 2.6 × 10⁻¹⁰ g L⁻¹. The coexistent metal ions can be separated, and thallium can be enriched by polyamide, which greatly improved the selectivity and sensitivity of the system. The method was applied to determine trace amount of thallium in wine, water and mineral samples, with satisfactory results.

Keywords:

• 3-p-chlorophenyl-5-(2′-arsenoxylphenylazo) rhodanine
• catalytic fluorescence analysis
• thallium(III)
• pre-concentration and separation

Acknowledgements

This work was financially supported by Science Research Foundation of Shandong Province, China (Y2007B07), Science Research Foundation of University of Jinan, China (XKY0817), National Eleventh Five-Year Plan, China (2006BAJ03A09), Postgraduate Innovation Program of Shandong Province (SDYY08030) and the National High-Tech Research & Development Program of China (No. 2007AA10Z430).