Cadmium detection via boron-doped diamond electrodes: surfactant inhibited stripping voltammetry

The deposition of cadmium on boron-doped diamond is investigated with square-wave anodic stripping voltammetry. The system was investigated in quiescent conditions, in the presence of an acoustic field and then in the presence of the neutral surfactant Triton® X-100. The effect of optimised insonation was to increase the sensitivity from 0.63 (under silent conditions) to 3.78 μA μM−1 and to reduce the limit of detection by an order of magnitude from 10−8 to 10−9 M. Measurements with or without insonation were found to deteriorate in the presence of the surfactant. Studies using AFM and chronoamperometry showed that this was due to inhibition of the deposition of the metal. Comparative data obtained for analogous measurements for copper on glassy carbon in the presence of industrial effluent, which also leads to signal deterioration under silent but not insonated conditions, showed that for this case also it was the nucleation of copper rather than the metal dissolution which was adversely affected.