Determination of ultratrace lead with bismuth film electrodes based on magneto-voltammetry

A novel method for the determination of Pb2+ with bismuth film electrodes (BFEs) based on magneto-voltammetry was investigated. In the presence of a 0.6 T external magnetic field, square wave voltammetry of Pb2+ was performed with BFEs. A high concentration of Fe3+ was added to the analytes to generate a large cathodic current during the preconcentration step. A Lorentz force from the flux of net current through the magnetic field resulted in convection. Then, more Pb2+ deposited onto the electrode and larger stripping peak currents were observed. BFEs that were prepared by simultaneously depositing the bismuth and Pb2+ on an electrode offered a mercury-free environment for this determination. This method exhibits a high sensitivity of 4.61 µA µM-1 for Pb2+ over the 1 × 10-8 to 1 × 10-6 M range. A detection limit as low as 8.5 × 10-10 M was obtained with only 1-min preconcentration. The method was successfully applied to determine Pb2+ in real water samples.