A Status Report on Electroanalytical Techniques for Immunological Detection

Immunoassays are commonly used for the detection of low levels of a specific target analyte or group of analytes. The search for new nonradioactive detection methods has resulted in a plethora of immunoassay techniques utilizing different types of labels, the most common being enzymes. Electrochemical immunoassays are based on modifications of enzyme immunoassays with the enzyme activities being determined potentiometrically or amperometrically. Other nonradioactive assays have been designed which are not adapted from spectrophotometric detection methods. Each of these assays, including electrochemical enzyme immunoassays, is discussed briefly in this chapter. In addition, various electrochemical immunosensors reported recently and focuses on the use of electropolymerized conducting polymers (CPs) in amperometric immunochemical sensors are discussed. An electrochemical immunosensor is described for the analysis of polychlorinated biphenyls using a CP-based immunosensor. The sensor produced adequate linear response characteristics and sensitivities that are comparable with results obtained using the enzyme-linked immunosorbent assay (ELISA) technique.