Catalytic adsorptive stripping voltammetry of Co(II)-dioxime-bromate systems at renewable amalgam film electrode

After 60 s of accumulation at −0.7 V in the supporting electrolyte containing 6.5 × 10−5 M DMG, 0.2 M BrO3− and 0.1 M ammonia buffer, cobalt may be determined in the concentration range of 5 × 10−10-1 × 10−7 M Co(II) by means of SW-CAdSV at the Hg(Ag)FE. The limit of detection was 1 × 10−10 M Co. The proposed method of cobalt determination was successfully applied and validated by studying the certified reference material TMRAIN-95 (water sample). The elaborated method ensures very sensitive determination of Co(II) as well as simultaneous estimation of Co(II) and Ni(II) in the presence of a 4000-fold excess of Zn(II).