Electrochemical detection of ionic mercury at boron-doped diamond electrodes

Boron-doped diamond (BDD) films were utilized for the first time to electrochemically detect mercury dissolved in solution via the initial deposition of metallic mercury, followed by anodic linear sweep voltammetry in the range from 10(-10) to 10(-5) M. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were employed. The extremely low background current for BDD electrodes compared to glassy carbon (GC) provides a strong advantage in trace metal detection. CV peak currents showed good linearity in the micromolar range. A detection level of 6.8 x 10(-10) M was achieved with DPV in 0.1 M KNO3 (pH = 1) for a deposition time of 20 min. Reproducible stripping peaks were obtained, even for the low, concentration range. A comparison with GC shows that BDD is superior. Linear behavior was also obtained in the mercury concentration range from 10(-10) to 10(-9) M.