Electrochemical detection platinum-working electrode

Jackson et al. [26] set miniaturized, battery-powered, high-voltage power supply conditions in NCE for the separation of dopamine and catecholamines with electrochemical detection. The authors varied platinum working electrode voltage from 25 to 200 V/cm for achieving low limits of detection. 

The measurements were performed with an usual setup for siuface-enhanced Raman spectroscopy The Raman spectra were measured with a Spex 1406 spectrometer, the samples were illmninated with a Spectroscopy Instruments argon ion laser (A = 514 nm, 30 mW) and the spectra were detected by a Princeton Instruments optical multichannel analyzer imder computer control. All experiments were performed in an electrochemical cell containing an inert platinum working electrode mechanically... 

Figure 10.223 Determination of sulfite in a platinum working electrode sample white white wine utilizing electrochemical detection, wine diluted 1 10 with deionized water Separator column lonPac ICE-AS1 eluent peaks (1) glycerol, (2) 1.5 mg/L sulfite (the sul-...

Electrochemical oxidation-reduction of eluting mixture components is the basis for amperometric electrochemical detectors. The three electrodes needed for the detection, the working (indicator) electrode, reference electrode, and auxiliary electrode, are either inserted into the flow stream or imbedded in the wall of the flow stream. See Figure 13.13. The indicator electrode is typically glassy carbon, platinum, or gold, the reference electrode a silver-silver chloride electrode, and the auxiliary a stainless steel electrode. Most often, the indicator electrode is polarized to cause oxidation of the mixture components... 

A flow injection system combined with an enzyme electrode was used to detect and quantify a variety of pesticides [41]. Photocrosslinkable polyfyinyl alcohol) was used to immobilise AChE onto platinum wire working electrodes. These were then placed inside a flow injection cell and the electrochemical response to injections of thiocholine measured. A series of measurements were made before and following the injection... 

Electrochemical sensors based on amperometric detection are popular small instruments that can be used to directly probe samples. The electrodes in these sensors do not always have to be made of metal, e.g. platinum or mercury, and do not always have to be bare. A commonly employed working electrode is the rotating disk electrode, which is preferred over the DME for easily reduced species and anodic reactions. It works by convection mixing of the solution so that fresh sample is constantly passed over the surface. 

This type of detector measures the current generated in an electrochemical cell at a fixed applied potential by the reduction or oxidation and an eluted analyte at the surface of a microelectrode. Sometimes this is called the counterelectrode (usually made of gold, platinum, or a glassy carbon) and auxiliary or working electrode and a reference electrode, usually Ag/AgCl. The mobile phase used will act as the supporting electrolyte for the redox reactions therefore, its composition is restricted to aqueous solvent mixtures. Amperometric detection is used for ions that have pKa values of greater than 7 and thus cannot be detected by conductivity detectors (because the formed products are weakly dissociated). 

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