Search

The effect of the sp2/sp3ratio in an unbalanced magnetron sputtered nanocarbon film electrode was studied for determining Cd2+and Pb2+by anodic stripping voltammetry (ASV). The signal-to-noise ratio in the ASV measurement improved as the sp3concentration in the carbon film increased because the noise current decreased with the increasing sp3 concentration. The detection limits with a carbon film containing 50% sp3were 0.25 and 1.0 μg L−1for Cd2+and Pb2+with high repeatability (Cd: 4.6% and Pb: 6.4%, n = 3). For a real sample measurement, a pretreatment system combining a photooxidation reactor and a cation exchange column was used to eliminate the interference from EDTA and Cu2+, which forms a stable complex or alloy with Cd2+and Pb2+. More than 99% of the interference was eliminated, and accurate signal currents for Cd2+and Pb2+were successfully obtained with the pretreatment system.