Voltammetric determination of trace mercury at a sonogel–carbon electrode modified with poly-3-methylthiophene

The sonogel–carbon electrode is a new class of sol–gel electrode that exhibit favourable mechanics and electrics properties to be used as electrochemical sensor. In this paper, a modified sonogel–carbon electrode is proposed to determine mercury at trace levels. The modified electrode is obtained by electropolymerization of 3-methylthiophene on the surface of a bare sonogel–carbon electrode. This electrode shows high selectivity and sensitivity and linear response towards Hg(II), with a detection limit of 1.4 × 10−3 mg l−1. The electrode is reusable by a simple chemical cleaning procedure. No deterioration was observed in the electrode response during at least 1 week of successive measurements.