A Review of the Electroanalytical Techniques: Voltametric

Introduction: Electro analytical techniques are a type of technique that work by measuring electrical quantities such as concentration of charge(ions), current change or potential of an electrode and can be divided into four main types, conductmetric, potentiometric, amperometric and voltametric, though all these techniques measure different quantities they are bound by a common thread of heterogeneity, which by placing an electrode in a solution creates a phase boundary separating identical solute molecules into two types and enabling those molecules at a distance and those near the electrode to take part in electrochemistry interactions[1], these methods all require at least a two electrode system, a working and reference electrode, except for amperometric and voltametric that need an additional auxiliary electrode [2] whereby an analyte is oxidized or reduced at the appropriate electrode[3], and the amount of analyte altered at that particular electrode depends on the amount of electricity transferred to that electrode [3].

Applications and state of the art voltametric techniques:

Since early days electroanalytical methods have proven of great importance since the introduction of the law of electrolysis by Michael Faraday in 1834 [3] and the invention of polarography by Jaroslav Hevrovasky in 1964, though many other scientists have also contributed to the development of these methods thus making them a viable source of analysis in many fields concerning physics and electrochemistry.

A rather interesting electroanalytical technique is voltametric that involves the application of a potential to a particular electrode and monitoring the current flowing through the electrochemical cell [] over a given period of time.

Voltametric cell set up and how it works: A voltametric cell consists of three electrodes, a reference electrode, an auxiliary electrode and a working electrode where the reduction and oxidation processes of the analyte take place at its surface, when the appropriate potential is applied the transport of new material to the electrode surface and the generation of a current are observed. Though there are various types of voltametric techniques they all apply this same fundamental electrochemical theory, some of these types include:-

Polarography:- a technique that uses a dropping mercury electrode (DME) as a working electrode, the DME working electrode has mercury drops at the end of the glass capillary with a drop life time of 0.5-2 seconds, with the calomel reference electrode and the auxiliary electrode being made of a platinum wire [4]

Solid electrode voltametry:- a technique whereby the working electrode is either platinum, carbon or gold, is sealed into a glass rod that rotated at 600rpm the analyte is purged of oxygen and "a supporting electrolyte is present" this techniques seems more advantageous to polarography since at 600rpm the sensitivity is increased five times, only disadvantages is that its susceptibility of solid electrodes to contamination due to adsorption effects [5],