Application of a nickel-microelectrode-incorporated end-column detector for capillary electrophoretic determination of alditols and alcohols

An end-column amperometric detector based on an incorporated Ni-microelectrode has been developed and used for the determination of alditols and alcohols in capillary electrophoresis. Satisfactory performance with respect to stability of background current, lowering of detection limit and reproducibility was obtained for the analysis of ten alditols and alcohols contained in a synthetic sample. For the studied system, the precision of migration time and peak current (in terms of relative standard deviation, with n=9) were of the ranges 0.52-1.4% and 2.2-4.7%, respectively. In the linear range 1.05-105 mg l(-1), a separation efficiency of about 121 000 theoretical plates per meter and a detection limit as low as 0.10 fmol were obtained. The effects of concentration of the separation electrolyte, separation potential, electrokinetic injection time, and applied potential on the response of the Ni-microelectrode-incorporated electrochemical detector were also studied. Application of this detection system was demonstrated by analyzing the alditol and alcohol contents in two alcoholic beverages.