Electrocatalytic detection of cobalt separated by ion exchange chromatography

Electrocatalytic effect: mechanism and application to ion chromatography

“…When Co2+ in a pH 4.4 buffer solution of tartaric acid-sodium tartrate flows past a carbon working electrode, where a potential of 0.95 V vs. ferri-ferrocyanide is applied, the electrocatalytic effect is observed. Very few metal ions, other than Co2+, cause this effect (8). In an attempt to better understand the electrode reaction, the eluent was altered and any resulting change in sample signal observed.…”

“…The eluting metal ions are detected by utilizing secondary constant-potential coulometric detection (1-3), by reverse-pulse reductive polarography (4), or by colorimetric methods following a postcolumn reaction with a metallochromic reagent (5)(6)(7). In 1979, Takata and co-workers (8) reported a novel electrochemical method for the trace-level determination of cobalt(II). The signal obtained with this technique was approximately 50 times that predicted by Faraday's law assuming a one-electron oxidation reaction.…”

Liquid chromatography with electrochemical and or spectrophotometric detection for automated determination of lead, cadmium, mercury, cobalt, nickel and copper

“…There is little doubt that the gross features of retention can be described by considering the interactions of solutes with the mobile phase. However, it has become increasingly clear that many of the more subtle features of solute retention, including selectivity within a group of closely related solutes, can be accounted for only by considering interactions in the stationary phase and/or at the stationary-mobile phase interface (5)(6)(7)(8)(9).…”

“…For example, cadmium from the production of pigments and storage batteries, lead from petrol, and mercury from the production of amalgams and medical formulas (3,4). Monitoring of cobalt can also be important (5) although toxicity is not usually an important factor for this element.…”