2,4,6-tri(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cobalt(II) determination by differential pulse anodic stripping voltammetry

A differential pulse anodic stripping voltammetry was developed for the sensitive and selective determination of Co(II) at 214.6-tri(3,5-dimethylpyrazoyl)-1.3.5-triazine modified carbon paste electrode in 0.1 mol l(-1) NH4Cl solution (pH 4.95). The oxidation peak of Co(II) was observed at 0.03 V(vs. Ag/AgCl) by scanning the potential in a positive direction. The analysis procedure consisted of an open circuit accumulation step in stirred sample solution. This was followed by medium exchange to a clean solution and subsequently an anodic potential scan was effect to obtain the voltammetric peak. The current was proportional to the concentration of the Co(II) ion in a range of 1 x 10(-8)-1 x 10(-6) mol l(-1) for 3 min accumulation and in the range of 1 x 10(-9)-1 x 10(-8) mol l(-1) for 5 min accumulation; most of metal ions do not interfere with the determination. The developed method was applied to Co(II) determination in potable water. (C) 2000 Elsevier Science B.V. All rights reserved.