DIFFERENTIAL-PULSE VOLTAMMETRIC ENZYME-LINKED IMMUNOASSAY FOR THE DETERMINATION OF HELICOBACTER-PYLORI SPECIFIC IMMUNOGLOBULIN-G (IGG) ANTIBODY

A differential pulse voltammetric enzyme-linked immunoassay for the de termination of helicobacter pylori (H. pylori) specific IgG antibody i n human serum has been developed. The method is based on coupling the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 that i s catalysed by horseradish peroxidase-IgG(HRP-IgG) conjugate with the electro-reduction of the enzymatic product to measure the activity of HRP-IgG. The latter reaction exhibits a sensitive differential pulse v oltammetric response at 0.1 V (versus Ag/AgCl) in pH 4.0 acetate buffe r solution. So, the H. pylori specific IgG antibody could be detected. The detection limit of present method for H. pylori specific IgG anti body was 1.0 units ml(-1), which was about seven times lower than that obtained by traditional spectrophotometric ELISA procedure. (C) 1997 Elsevier Science B.V.