Disposable microfabricated 3-electrode electrochemical devices with integrated antimony working electrode for stripping voltammetric determination of selected trace metals

This work reports the fabrication of novel 3-electrode integrated devices featuring an Sb-film working electrode and Ag and Pt planar strips serving as the reference and counter electrodes, respectively. The deposition of the metal layers was carried out by sputtering of the respective metals on an oxidized silicon substrate, while the electrodes were patterned via a metal mask and isolated using a simple photolithographic step. The utility of these devices was tested for the simultaneous trace determination of Pb(II) and Tl(I) by square-wave anodic stripping voltammetry (SWASV) in strong acidic medium (0.05 mol L−1 phosphoric acid) in which the antimony sensor exhibited advantageous electroanalytical performance. The limits of detection were 0.7 μg L−1 for Pb(II) and 0.9 μg L−1 for Tl(I), and the within-sensor reproducibility was 3.2% for Pb(II) and 3.9% for Tl(I) at the 20 μg L−1 level (n = 12). The applicability of these novel sensors was demonstrated for the analysis of a spiked mineral water sample.