subject: What Is Voltammetry Analysis And When Is It Used [print this page] Voltammetry is an analytical method (or more accurately, a set of analytical methods) which are used to determine the properties of an analyte through taking a measurement of the reactivity of the analyte to an electrical charge while the potential of the current is varied. The basic setup for this analysis involves putting one electrode in contact with the analyte, another electrode which is not in contact with the analyte (this electrode forms the other half of the cell), a potentiometer and a amperage meter to measure the electrical charge and determine the amount of resistance of the analyte to the current.
The difficulty with these most basic of voltammetry setups is in maintaining a constant potential during the process; which makes accurate results somewhat problematic (to understate the case). For this reason, the usual process is to use two electrodes in order to divide the labor of referencing the potential and supplying electrons during the process. One electrode is used solely as a reference electrode, with no current passing directly through it during the voltammetry analysis.
It is instead the other, auxiliary electrode which bears this responsibility; something which can require it to reach the extremes of its potential along the solvent window and reduce or oxidize the voltammetry electrolyte or solvent being used. Along with the working electrode, the auxiliary and reference electrodes are the basis of the 3-electrode system now in currency, as well as those voltammetric systems which use a larger number of electrodes.
As for the electrodes themselves, these are pieces of equipment which need to be well maintained, with regular cleaning being a necessity. The reference and working electrodes vary depending on the particular demands of the this analysis being performed and there are many different standards in place for different applications.
The auxiliary electrode, however is not nearly so specialized and in fact almost any electrode can be used in this role, provided that it is appropriately conductive and will not react with the analyte solution in such a way as to affect the outcome of the voltammetry procedure. In general, a ferrocene/ferrocenium pair is the standard for analytical applications which involve non-aqueous solutions.
Different types of voltammetric setups are used for different applications in the sciences and in the research and development and quality control departments of manufacturers. Dissolved oxygen content can be determined through voltammetry analysis, something which is of use in clinical, research, earth sciences, water purification and a wide range of other applications. Cyclical voltammetric studies are the most commonly used type and tend to be the first procedure performed, since it provides a wider scope of data as well as giving more detailed information on many electrochemical reactions.
Voltammetry is used to determine valuable information about analytes in pharmaceutical research, development and production, the life sciences, environmental science and other sectors; and the continuing development of more sophisticated and specialized electrodes for have given this analytical technique a growing importance, even in fields where voltammetry analysis was barely used in years past.
