Self cleaning electrochemical detector and cell for flowing stream analysis

摘要

An improved electrochemical cell and detector which is especially suited for analysis of rapidly changing flowing streams such as found in high performance liquid chromatography is disclosed. A uniquely designed jet made of microbore drawn capillary tubing permits the construction of a cell for very low flow rates that still retains true wall-jet hydrodynamics. The invention prevents changes in cell response in time by periodically cleaning a working electrode in a novel way. Cleaning and detection are both accomplished on a time scale much shorter than the fastest liquid chromatograph peaks by means of a unique three electrode cell design utilizing a small diameter, low capacitance, metal working electrode situated close to a reference electrode. Cleaning is accomplished by means of a non-square wave periodic waveform which is effective in cleaning a wide variety of contaminants through the oxidation and reduction of the working electrode and/or solvent prior to application of one or more working potentials while providing a stable, reproducible detector. The detector thus provides improvements in both sensitivity and bandwidth over the prior art.