Electrochemical behavior of progesterone at an ex situ bismuth film electrode

An ex situ bismuth film electrode (BiFE) was used for the electrochemical study of the hormone progesterone. Two peaks were observed by cyclic voltammetry, at −1.68 V and −1.47 V, respectively, associated with the reduction and oxidation reactions of progesterone in 0.1 mol L−1 Britton-Robinson solution at pH 12.0, in agreement with a quasireversible electrode process. In relation to the mechanism, an adsorption-controlled reaction rate with one electron involved in the electrochemical step was observed. Square-wave adsorptive stripping voltammetry was used for the analytical procedures after accumulation of the progesterone for 60 s at −1.0 V. A peak current at −1.63 V related to the reduction of progesterone was obtained, which increased linearly with the hormone concentration in the range of 0.40-7.90 μmol L−1 (R2 = 0.9983). The limit of detection attained was 0.18 μmol L−1. The method was applied in the determination of progesterone in four pharmaceutical samples with satisfactory results being obtained compared with a spectrophotometric method.