Electroanalytical Technique (Voltammetric techniques) critical review Literature

Electroanalytical Technique (Voltammetric techniques) critical - Literature review Example When compared to methods such as chromatography which uses relatively large amounts of sample with low sensitivity, voltammetry techniques will require few amounts of sample while affording high sensitivity. In addition, wide range of concentration can be used in voltammetry. Voltammetric techniques reduces ions at the electrodes which are usually three the working electrode, auxiliary electrode and reference electrode. Given such wide capabilities, voltametric techniques have been amenable to use in biochemical analyses, environmental studies, plating analysis, pharmaceuticals as well as waste water analyses among other useful applications. Instrumentation In voltammetry basic instruments include the electrochemical cell composed of a three electrodes configuration; a voltamperomeric analyser formed by the potentiostat coupled to a computer system. Working electrode provides the response of the analyte response due to the applied potential. Examples of electrode include mercury electrodes such as Hanging drop mercury electrode (HDME), static drop mercury electrode (DME) and rotating disk electrodes (RDE).Auxiliary electrode is tasked with completing the circuit between the potentiostat and working electrode and examples include platinum and glassy carbon electrodes. Reference potential to the auxiliary and working electrodes is provided by the reference electrodes e.g. Ag/AgCl in KCl and Hg/HgCl in KCl(l). Drugs analysis applies various separation-based techniques such as chromatography and electrophoresis. These techniques are important when following-up metabolism of the drug in complex samples such as urine. However, electroanalytical methods such as voltammetry become vital when samples being analysed contain a single physiologically active component such as the active ingredient in a particular drug. Electroanalytical methods offer advantages such as simple handling of the procedures, high sensitivity, better accuracy and faster speed relative to separation techniques – chromatography and electrophoresis. They also utilise cheaper instrumentation and low cost chemicals. Two electroanalytical techniques exist with the first one being where the surfaces of electrodes are continuously renewed for instance in the dropping mercury electrode. Techniques employing this type of electrode are called polarography and they mainly differ in the approach of application of voltage to the dropping mercury electrode (DME). The second class of techniques belong to techniques which use electrodes whose surfaces are not renewed. Common electrodes in this group include the hanging mercury drop electrode (HMDE). Techniques that record current-voltage curves with these electrodes are referred to voltammetry. Voltammetric Techniques Voltammetric methods have been used in the determination of trace levels of platinum group metals which have traditional employed spectroscopic methods in their determination (Locateli, 2007). Such metals include Osmium, Ruthenium and Iridium. One of the approaches used in determination of these metals is the differential pulse voltammetry (DPV). The electrodic processes associated with platinum group metals (PGMs); however, present challenges such as the low reversibility degree thereby limiting detection of these trace metals (Kritsotakis et al., 1985). Presented with such challenge of detection limits, some methods have been worked out to con centrate these trace metals onto the working electrode. One technique which has been developed is the adsorptive