On-line electrochemical redox derivatization for enhancement of separation selectivity of liquid chromatography

An on-line electrochemical redox derivatization technique for enhancement of separation selectivity of HPLC using an electrolytic flow cell is presented. This HPLC system consists of two separation columns and a small electrolytic flow cell placed between them. A redox derivatization reaction proceeds in the electrolytic flow cell so that an analyte compound migrates in its original form in the first column, while it moves in its oxidized or reduced form in the second column. The selective separation of an analyte compound has been achieved, because redox reactions specific for the analyte in the electrochemical derivatization unit can be controlled by alteration of potential applied to the cell. A successful application of this method to the separation and determination of cobalt in a stainless steel is demonstrated.