HOMOGENEOUS AMPEROMETRIC IMMUNOASSAY FOR DIGOXIN

A homogeneous spectrophotometric EMIT immunoassay for the measurement of digoxin has been converted to an amperometric immunoassay format ca pable of analysing digoxin in diluted serum. NADH produced by glucose- 6-phosphate dehydrogenase (G6PDH) labelled digoxin was detected ampero metrically by its rapid, efficient oxidation at platinized activated c arbon electrodes (PACE) poised at +150 mV vs Ag/AgCl. The new amperome tric procedure resulted in a simplified assay protocol with a decrease d overall assay time, enhanced NADH detection and minimal sample pretr eatment.