A MICROELECTRODE FLOW AMPEROMETRIC DETECTOR FOR WATER-SOLUBLE POLYMERS

A single electrode assembly, consisting of a platinum wire (20- or 25-mu m diameter) microelectrode and a palladium coating (as auxiliary/pseudo-reference electrode) on the glass tubing housing the microelectrode, has been utilized as a flow amperometric sensor for water-soluble polymers. An ordinary 3-V dry cell was used as voltage source. Amounts of injected polymer were in the range 0.01-260 mu g. The detector performance was superior to that of a differential refractive index detector in terms of limits of detection (sub-mu g levels of polymer), baseline stability, and reproducibility of analytical signal.