Abstract: The cyclic voltammetry(CV) and the square-wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 {mmol/L} HClO₄+ 10 mmol/L NaCl was selected as the supporting electrolyte. The calibration plots for Tl(Ⅰ) concentration in the range of 2×10^-9—1×10^-7 mol/L were obtained. The detection limit was 5×10^-10 mol/L. For the solutions of 4.0×10^-9 mol/L thallium added before the urine sample pretreatment procedure, the average recovery was 105.6% with a relative standard deviation(RSD) of 15.5%.

Key words: Thallium(Ⅰ), Underpotential deposition, Silver rotating disk electrode, Cyclic voltammetry, Square-wave anodic stripping voltammetry