PULSED ELECTROCHEMICAL DETECTION OF THIOLS AND DISULFIDES FOLLOWING CAPILLARY ELECTROPHORESIS

Pulsed electrochemical detection (PED) following capillary electrophor esis (CE) has been applied to the direct detection of thiocompounds. B oth reduced and oxidized thiol moieties are detected without the need of derivatization. Thiocompounds can be detected over a wide range of pH conditions (i.e., pH 0-14), and except for pH, their response is re latively unperturbed by buffer composition. Integrated pulsed amperome tric detection (IPAD) results in more stable baselines, eliminates oxi de-induced artifacts, and yields lower limits of detection than other PED waveforms. Mass detection limits using optimized IPAD waveforms ar e typically 2 pg (5 fmol) or less. The high selectivity of PED for thi ocompounds reduces sample preparation and produces simpler electropher ograms of complex samples containing these biologically significant co mpounds.