Determination of mercury in process and lagoon waters by inductively coupled plasma-mass spectrometric analysis after electrochemical preconcentration: comparison with anodic stripping at gold and polymer coated electrodes

A combined electrochemical-inductively coupled plasma-mass spectrometry (EC -ICP-MS) method for the determination of trace mercury in water samples is presented, It takes advantage of the electrochemical preconcentration of me rcury onto a gold spiral electrode followed by ICP-MS analysis after the el ectrochemical reoxidation of deposited mercury in pure supporting electroly te. The advantages of the EC-ICP MS approach with respect to conventional I CP-MS, are the increased sensitivity and the elimination of the effect of i nterfering substances eventually present in the sample, EC-ICP-MS is applied to the determination of nanomolar and subnanomolar con centrations of mercury(II) ions in real samples such as process waters (fro m a chlor-alkali plant) and lagoon waters (from Venice channels). Analytica l performances obtained by EC-ICP-MS are discussed and compared with those obtained by anodic stripping voltammetry at gold and at Tosflex-coated glas sy carbon electrodes, (C) 2001 Elsevier Science B,V. All rights reserved.