Determination of Trace Tl(I) by Anodic Stripping Voltammetry on Novel Disposable Microfabricated Bismuth-Film Sensors

This work reports the trace determination of Tl(I) by square-wave anodic stripping voltammetry (SWASV) on novel microsensors equipped with a bismuth-film electrode (BiFE). The sensors were fabricated by a multistep microfabrication approach combining sputtering (to deposit the electrode materialm, bismuth- and the insulator SiO2, on the surface of a silicon wafer) and photolithography (to define the geometry of the sensor). The effect of the preconcentration time, the preconcentration potential and the SW stripping parameters were investigated. Using the selected conditions, the 3 sigma limit of detection was 0.6 mu g L-1 of Tl(I) at a preconcentration time of 240 s and the percent relative standard deviation was 4.3% at the 10 mu g L-1 level (n = 8). In order to eliminate the interference caused by Pb(II) and Cd(II). EDTA was added in the sample solution The method was successfully applied to the determination of Tl(I) in a certified lake water sample. These new sensors exhibit excellent mechanical stability and offer wide scope as mercury-free disposable sensors for trace metal analysis.