Electroanalytical Techniques and Instrumentation in Food Analysis
Electrochemical techniques are inevitable tools in almost every chemical and biochemical research laboratory. In addition to their application in fundamental studies of oxidation and reduction processes to unravel reaction mechanisms, these techniques are also used in studying the kinetics and thermodynamics of electron and ion transfer processes . Moreover, electrochemical techniques have also proven to be useful tools for the study of adsorption and crystallization phenomena at electrode surfaces . Among the electrochemical techniques applied in food analysis, the
principal ones are polarographic and voltammetric techniques . Their wide application is attributed to the relatively cheap instrumentation, very good sensitivity with wide linear concentration ranges for both inorganic and organic compounds, rapid analysis times (in seconds), and simultaneous determination of several analytes. Currently, polarographic techniques have almost been completely excluded from research laboratories, and are being replaced by the more sophisticated voltammetric techniques . Voltammetry (abbreviation of volt-amper-metry) is a branch of electrochemistry that was developed by the discovery of polarography in 1922 by Jaroslav Heyrovsky (Nobel Prize in 1959). A major breakthrough in voltammetry was made in the early 1960s, when an expanded repertoire of analytical methods was reported, appearing in parallel with the corresponding well-developed theories [1,4]. At the same time, these developments led to enhanced sensitivities obtained with the voltammetric techniques. The excitation signal in all voltammetric techniques is the applied potential difference (or potential as it is commonly referred to), E, between the electrodes, whereas the monitoring output parameter is the resulting current, I, ﬂowing through the electrochemical cell.