Anodic stripping voltammetric determination of traces and ultratraces of thallium at a graphite microelectrode

A bare graphite microelectrode was used for the anodic stripping voltammetry determination of traces and ultratraces of Tl+ ion in aqueous solutions at pH 3.5, in the presence of a 1 × 10−3 mol L−1 EDTA solution. The proposed method, validated and tested at ultratrace level in environmental water samples, showed low detection and quantification limits (0.01 and 0.03 μg L−1, respectively) and excellent capability to determine the analyte also in the presence of a very high excess of interfering ions, i.e. 2200:1 and 10,000:1 (w:w) for Pb2+ and Cd2+, respectively. Furthermore, the wide linearity range, the absence of bias, the low time required for each measurement and the low cost of the instrumentation needed are additional factors supporting the application of such a method as a screening tool in the direct determination of thallium ionic species in environmental samples.