Instruments for Voltammetric Techniques

Voltammetry comprises a series of electroanalytical techniques in which information about the analyte is collected by measuring the current as a function of the potential applied to the WE [53]. The specific name of the technique is typically associated with the waveform applied to the WE. 

In the simplest case of voltammetry, a constant potential is applied to the detection electrode and the current is recorded as function of time. Being the most straightforward electrochemical technique that can be applied for detection of readily electroactive compounds, it requires simple instrumentation and has the advantages of being inexpensive and easily integrated with a variety of instruments including HPLC [54] and capillary electrophoresis [10, 55-57]. 

Several companies now offer standard bench-top instrumentation that can perform amperometry with background currents that yield to a LOD in the micromolar to nanomolar range. As expected, this range depends on the analyte, technique, and experimental 

Amperometry is probably one of the most common electroanalytical techniques used in food analysis and there are numerous examples in the literature. Among others, it is worth mentioning analysis of cholesterol [72], vitamins [73, 74], carbohydrates [75, 76], antioxidants [4, 77-79], pesticides [80, 81], and toxins [82]. It is also important to point out that, although not discussed in this chapter, the same instrumental configuration used in amperometry can be used for the development of amperometric biosensors [83-86], electrochemical ELISA assays [87-89], and electrochemical tongues [90,91]. 

As it can provide some of the most basic electrochemical information related to the reactivity of the selected analyte (peak potential and peak current) most instruments that perform amperometry can also perform some of the most basic voltammetric techniques. These techniques determine the current as a function of the potential applied to the WE (in a conventional three-electrode cell) and can be performed with relatively simple instrumentation [105,106]. As different signals can be combined in the input ports of the instrument, multiple variations of the technique have been developed including cyclic voltammetry, linear sweep voltammetry, linear sweep stripping voltammetry, stripping voltammetry [107, 108], fast-scan cyclic voltammetry [109], square-wave voltammetry [110],and sinusoidal voltammetry [111]. 

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