FAST-PULSED ELECTROCHEMICAL DETECTION AT NOBLE-METAL ELECTRODES - THEFREQUENCY-DEPENDENT RESPONSE AT GOLD ELECTRODES FOR CHROMATOGRAPHICALLY SEPARATED CARBOHYDRATES

Waveforms used in pulsed electrochemical detection (PED) have frequenc ies of ca. 1 Hz when optimized to give a maximum signal-to-noise ratio (S/N) for carbohydrates. However, higher frequencies are desired for applications of PED to capillary electrophoresis (CE) and microcolumn liquid chromatography (MLC), which can produce narrow elution peaks. M inimization of the time periods for oxidative cleaning and reductive r eactivation in PED waveforms generated by the Dionex Pulsed Electroche mical Detector allows the increase in waveform frequency to ca. 3 Hz w ithout change in the traditional time period of 200 ms, prescribed for integration of the anodic current. However, further increase in frequ ency requires a decrease in the integration period with a correspondin g loss of signal strength.