Variation in PED response at a gold microelectrode as a function of waveform parameters when applied to alditols and carbohydrates separated by capillary electrophoresis

Abstract

AbstractResults are presented from a systematic study of the noise (N) and peak‐to‐noise ratio (P/N) obtained for pulsed electrochemical detection (PED) at a gold micro‐wire electrode applied to a mixture of alditols and monosaccharides separated by capillary electrophoresis (CE). The electrode potentials and time periods for oxidative cleaning and reductive reactivation of the electrode were held constant in the PED waveform at minimum allowable values and the time period for digital integration of electrode current (tint) was varied from 50 to 800 ms by 50‐ms intervals. The value of N was virtually independent of tint and P/N increased approximately as a linear function of tint in the range 50–200 ms corresponding to waveform frequencies in the range 4.5–2.7 Hz. A detection limit of 9 fmol glucose was determined for a 4‐nL injection using tint = 200 ms.