Homogeneous Amperometric Immunoassay for Digoxin

Abstract

Abstract A homogeneous spectrophotometric EMIT immunoassay for the measurement of digoxin has been converted to an amperometric immunoassay format capable of analysing digoxin in diluted serum. NADH produced by glucose-6-phosphate dehydrogenase (G6PDH) labelled digoxin was detected amperometrically by its rapid, efficient oxidation at platinized activated carbon electrodes (PACE) poised at +150 mV vs Ag/AgCl. The new amperometric procedure resulted in a simplified assay protocol with a decreased overall assay time, enhanced NADH detection and minimal sample pretreatment.