In the present work a gold modified pencil graphite electrode (GPGE) was used for the determination of l-dopa present in the aqueous extracts of Mucuna pruriens seeds (MPS), Mucuna pruriens leaves (MPL) and Commercial Siddha Product (CSP). The GPGE shows excellent electrocatalytic activity towards the oxidation of both l-dopa and ascorbic acid (AA), with the separation of peak potential of 98 mV. The differential pulse voltammetric (DPV) results indicated that the detection limit for l-dopa was 1.54 mM (S/N = 3). This method can be successfully applied for the determination of l-dopa in real samples.

The barium hydrogen phosphate modified carbon paste electrode (BHP-CPE) was prepared as an electrochemical sensor. Its propensity towards the simultaneous determination of Cd(II) and Pb(II) has been demonstrated with differential pulse anodic stripping voltammetry (DPASV) in the potential window between À1.2 V to À0.4 V. Important operational parameters such as pH of the solution, deposition potential and deposition time have been optimized. Under the optimized conditions, calibration curves were linear in the concentration range 1 10 À8 to 8 10 À8 M on BHP-CPE and 1 10 À8 to 5 10 À8 M on Nafion-BHP-CPE. Experiments disclosed that BHP-CPE and Nafion-BHP-CPE exhibit good performance for the simultaneous determination of Cd(II) and Pb(II).