Detection of metal ions without interference from dissolved oxygen by reverse pulse amperometry in flow-injection systems and liquid chromatography

Reverse pulse amperometry (r.p.a.) is used to monitor fluid streams for the presence of electroactive metal ions using a mercury electrode without the requirement of deaeration. The technique is based on the application of an unsymmetrical square wave with a large negative initial potential for deposition of the metal ion followed by a positive potential pulse for anodic stripping of the metal. The analytical signal is measured during the stripping process at a potential where dissolved oxygen is not reduced. R.p.a. is applied at a polarographic detector in flow-injection systems and ion-exchange chromatography for detection of several ions of transition and heavy metals in aqueous solutions.