Quantitative and qualitative information from single coulostatic decay curves

Coulostatic pulse amperometry for liquid chromatography/electrochemistry detection

“…Instrumentation. The microprocessor-controlled coulostat system is the same as that previously described (18). New software was written to accomplish the control and data acquisition for the CPA technique.…”

“…As the solution resistance increases, the amplifier must reach a higher output voltage in order to pass the desired current through the cell. Our instrument uses a high voltage (±150 V) amplifier just for this reason (18). A current of 1 µ (very large by LCEC standards) could be passed through a cell with a resistance of 150 (orders of magnitude larger than typical) between the working electrode and counterelectrode.…”

“…The development of computer-controlled electrochemical instrumentation has prompted a rebirth of interest in coulostatic analysis (18,21,22). In coulostatics, a charge pulse of known coulombic content is injected into a cell on a time scale much more rapid than the time scale for electron transfer between the electrode and electroactive species in solution.…”

“…Furthermore, CPA should allow electrochemical detection for LC systems in which the mobile phase is of low conductivity. In earlier reports we have demonstrated use of coulostatics as a rapid scanning voltammetric technique (18) and preliminary results for application of coulostatic detection in flowing streams (19) and liquid chromatography (20). This paper details the development and application of an LCEC detector using coulostatic pulse amperometry.…”