Analysis of Ag(I) Biocide in Water Samples Using Anodic Stripping Voltammetry with a Boron-Doped Diamond Disk Electrode

The electroanalytical performance of a new commercial boron-doped diamond disk and a traditional nanocrystalline thin-film electrode were compared for the anodic stripping voltammetric determination of Ag­(I). The diamond disk electrode is more flexible than the planar film as the former is compatible with most electrochemical cell designs including those incorporating magnetic stirring. Additionally, mechanical polishing and surface cleaning are simpler to execute. Differential pulse anodic stripping voltammetry (DPASV) was used to detect Ag­(I) in standard solutions after optimization of the deposition potential, deposition time and scan rate. The optimized conditions were used to determine the concentration of Ag­(I) in a NASA simulated potable water sample and a NIST standard reference solution. The electrochemical results were validated by ICP-OES measurements of the same solutions. The detection figures of merit for the disk electrode were as good or superior to those for the thin-film electrode. Detection limits were ≤5 μg L^–1 (S/N = 3) for a 120 s deposition period, and response variabilities were