Effect of surface-active compounds on voltammetric stripping analysis at the mercury film electrode

The effects of various organic compounds on the differential-pulse anodic-stripping voltammetric response at the in-situ plated mercury film electrode are explored. These effects vary from metal to metal and from one organic compound to another. The most pronounced effects are observed in measurements of copper. The main effect of the organic compound is to depress the peak current rather than change the peak shape or potential. The differences between the organic interferences observed at the mercury film electrode and those reported at the hanging mercury drop electrode are explained by the different morphology and geometry of the two electrodes. The implications of these interferences for the reliability and feasibility of stripping measurements in natural waters are discussed. Gelatin, camphor, humic acid, starch, agar, sodium dodecyl sulphate and albumin were used as representative organic compounds, and cadmium, lead, and copper as test metal ions.