Voltammetric behavior and trace determination of Pb2+ at a mercury-free screen-printed silver electrode

Screen-printed silver electrodes (AgSPEs), without chemical modification, has been investigated as disposable sensors for the measurement of trace levels of Pb2+. potential segment analysis indicates that the formation of underpotential and bulk depositions of Pb is not strongly coupled on the AgSPE. The possibility of determining Pb2+ at trace levels using the reversible underpotential deposition peak was examined by square-wave anodic stripping voltammetry without removal of oxygen. Under the optimized analytical conditions, the obtained sensitivity, linearity, and detection limit are 0.355 muA/ppb, 5-80 ppb (r = 0.9992), and 0.46 ppb (S/N = 3), respectively. The electrode is quite stable for repetitive measurements. The interference effect was thoroughly studied with various metals and no significant change in current was found in the determination of 5 ppb Pb2+. The practical applications were demonstrated to measure trace Pb2+ in natural waters. (C) 2002 Elsevier Science B.V. All rights reserved.