ENZYMATIC ELECTROCATALYSIS AS A STRATEGY FOR ELECTROCHEMICAL DETECTION IN HETEROGENEOUS IMMUNOASSAYS

An extraction type enzyme immunoassay taking place directly at the surface of a glassy carbon electrode and based on electrocatalytic detection of enzyme labeled antibody is described. Such a configuration, where the carbon electrode is both the immunological solid phase and the electrochemical detector, ensures a proximity at molecular level between catalytic and electrochemical sites. The amperometric detection of the immobilized enzyme activity is thus very sensitive (better than 10** minus **1**5 mol/cm**2 of electrode surface) and the overall sensitivity of the assay may be modulated by the choice of the ratio between the assay volume and the capture solid phase area.