B. Limoges et al., REDOX CATIONIC OR PROCATIONIC LABELED-DRUGS DETECTED AT A PERFLUOROSULFONATED IONOMER FILM-COATED ELECTRODE, Journal of electroanalytical chemistry [1992], 402(1-2), 1996, pp. 175-187
With the aim of developing a new type of immunoassay with electrochemi
cal detection, a Nafion(R) film-modified electrode was used as an ampl
ifying sensor to detect redox cationic labeled drugs by square-wave vo
ltammetry, A series of amino drugs was labeled with three model redox
labels, i.e. cationic cobaltocenium and procationic ferrocene and nitr
oxide groups. Several parameters were involved in the optimization of
the analytical properties of the sensor, i.e. film processing and film
thickness, accumulation time, ionic strength and ethanol content. The
preconcentration of the labeled drugs was impeded by the competitive
accumulation of hydrophobic amines. The accumulation process of the pr
ocationic labeled drugs was influenced significantly by the potential
applied during accumulation, and their strong non-specific binding wit
h proteins was observed in the presence of serum. Therefore the choice
of cobaltocenium as a label was preferred. Optimized conditions were
defined, which took into account these various aspects. The avidin-bio
tin system was proposed as an applicable extension of this approach.