Capillary electrophoresis and electrochemical detection with a conventional detector cell

The performance of a commercially available electrochemical detector cell has been evaluated for use in capillary electrophoresis (CE). It was shown that with proper installation of the capillary, the zone broadening caused by the cell is limited by the depletion of the analytes on the electrode surface. Despite the relatively large geometric volume of the cell, its contribution to zone widths was therefore only in the order of 1-2 s. When coupled to a CE set-up, plate numbers up to 100 000 could be obtained. With a I-mm diameter glassy carbon electrode the detector noise was 3-5 pA, depending on the applied separation voltage. With this noise level detection limits of 10(-8) mol l(-1) could be obtained. The cell has been used for the determination of catecholamines, chlorophenols and o-phthalaldehyde derivatives of amino acids. (C) 1998 Elsevier Science B.V.