Competitive binding, electrochemical detection

Immunoassays, electrochemical — A quantitative or qualitative assay based on the highly selective antibody-antigen binding and electrochemical detection. Poten-tiometric, capacitive, and voltammetric methods are used to detect the immunoreaction, either directly without a label or indirectly with a label compound. The majority of electrochemical immunoassays are based on -> voltammetry (-> amperometry) and detection of redox-active or enzyme labels of one of the immunochemical reaction partners. The assay formats are competitive and noncompetitive (see also -> ELISA). 

Ducey M. W., Smith A. M., Gno X. A., and Meyerhoff M. E., Competitive nonseparation electrochemical enzyme binding immnnoassay (NEEIA) for small molecnle detection, Anal. Chim. Acta., 357(1-2), 5-12, 1997. 

There are many other examples of competitive electrochemical immunoassays and immunosensors for detecting clinically important analytes [12-14], Despite simplicity, a disadvantage of competitive immunoassays is that labeling the analyte may reduce, or totally remove, its binding affinity for antibody. This would occur if the analyte were labeled at a site that is closely associated with an epitope. 

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