Flow injection measurement of lead using mercury-free disposable gold-sputtered screen-printed carbon electrodes (SPCE)

Screen-printed sensors are promising devices for disposable, cheap and reliable environmental monitoring. In previous studies, workers have used mercury-coated electrodes to allow stripping voltammetry to be performed. In this paper, we describe a disposable sputtered gold sensor which allows underpotential analyte preconcentration and avoids the environmental contamination associated with mercury-based sensors. It is used in combination with a specially fabricated thin-layer flow cell for stripping analysis. The sensor consists of a screen-printed strip with three electrodes; gold coated over carbon-silver ink as the working electrode, silver-silver chloride ink as the pseudo reference electrode, and a carbon-silver ink as the counter electrode. The optimized flow injection (FI) system allows the convenient monitoring of micrograms per litre lead concentrations following short deposition times (detection limit 0.8 mug l(-1) at 120 s deposition). The method was evaluated by determining lead in spiked drinking and tap water samples; the recoveries of Pb2+ were 103% (R.S.D. 2.8%) and 97.9% (R.S.D. 7.1%), n = 5, respectively. Measurements in the presence of typical interferences such as copper, cadmium, zinc, iron, chromium, and mercury are reported. (C) 2003 Elsevier Science B.V. All rights reserved.