Micellar electrokinetic capillary chromatography of vitamin B6 with electrochemical detection

Abstract

A system for interfacing electrochemical detection with micellar electrokinetic capillary chromatography is demonstrated. This system couples the separation column to a short length of the same column material together with a section of porous graphite tubing which forms an electrically conductive joint. The joint is immersed in a buffer reservoir together with the ground electrode of the high-power source (15 kV). The reservoir is electrically insulated from the electrochemical cell containing the carbon fibre detector. This configuration effectively separates the detector from the high separation potential applied. Amperometric detection with micellar solutions is demonstrated for a mixture of B6 vitamers on a 50 μm I.D. column. A detection limit of ca. 4 fmol is obtained. The linear dynamic range of the calibration plot is slightly over two orders of magnitude (from ca. 1 to 200 ppm). © 1991.