Tin film sensor with on-chip three-electrode configuration for voltammetric determination of trace Tl(I) in strong acidic media

The present work describes the trace analysis of Tl(I) in acidic medium (0.05 mol L−1 nitric acid) by square wave anodic stripping voltammetry (SWASV) at a tin film sensor with novel configuration. This “green” electroanalytical device features on-chip metal film electrodes (a Sn-film working electrode, a Ag-film reference electrode and a Pt-film counter electrode), fabricated by sputtering the respective metals on a silicon chip. The effect of preconcentration time, preconcentration potential and SW stripping parameters on the Tl(I) detection was studied in detail. The limit of detection for Tl(I) was 1.1 μg L−1, while the % relative standard deviation at the same sensor was 5.2% at the 10 μg L−1 level. Finally, the sensors were successfully applied to the direct determination of Tl(I) in an acidified certified lake water sample.