Digoxin homogeneous immunoassay

Separation-free, homogeneous immunoassay protocols offer several advantages in comparison to heterogeneous methods. Because no separation is involved, the number of procedural steps is decreased, which decreases the time required per assay. Additionally, because the physical transfer step is avoided, potential sample loss related to this step is eliminated. Drugs with low molecular weights (amphetamines, digoxin) are commonly measured by separation-free homogeneous immunoassay protocols. ... 

Homogeneous electrochemical enzyme immunoassays for both phenytoin and digoxin have been developed. In both cases the label was glucose-6-phosphate dehydrogenase, which catalyzes the reduction of NAD to NADH. The NADH produced was detected by LCEC at a carbon paste electrode. 

H. Qi and C. Zhang, Homogeneous electrogenerated chemiluminescence immunoassay for the determination of digoxin. Anal. Chim. Acta 501, 31-35 (2004). 

FA Chen, SL Pentoney, Jr. Characterization of digoxigenin-labeled beta-phy-coerythrin by capillary electrophoresis with laser-induced fluorescence application to homogeneous digoxin immunoassay. J Chromatography 680 425-430, 1994. 

Suzawa T, Ikaiiyama Y, Aizawa M (1994) Multilabeling of ferrocenes to a glucose oxidase-digoxin conjugate for the development of a homogeneous electroenzymatic immunoassay. Anal Chem 66 3889-3894... 

Fig. 17. Homogeneous enzyme immunoassay with column switching LCEC for digoxin calibrators of marked concentration in ng/ml. —NADH peaks. Enzyme reaction sampled at 2 and 7 min for each calibrator.

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