Nanostructured Bismuth Film Electrode for Detection of Progesterone

Abstract

Progesterone is an important hormone responsible, among others, for maintaining pregnancy via inhibition of uterus muscles activity; thus, following its concentration levels in pregnant women is of immense importance in the endeavor to prevent premature birth. In this work, the nanostructured bismuth film electrode (nsBiFE) was studied for detection of progesterone in neutral medium. Due to the ability to accumulate progesterone at the nsBiFE, the adsorptive cathodic stripping voltammetry was beneficially exploited. The nsBiFE was prepared on the surface of a glassy carbon supporting electrode and several parameters influencing the detection of progesterone were investigated. The nsBiFE exhibited superior electroanalytical characteristics in comparison to other bismuth-based electrodes and unmodified glassy carbon electrode together with satisfactory response toward low concentrations of progesterone, which are consistent with clinically significant levels.

Keywords: adsorptive cathodic stripping voltammetry; nanostructured bismuth film electrode; nsBiFE; premature birth; progesterone.

Figure 1

Chemical structure of progesterone and its electrochemically active sites marked in red.

Figure 2

Adsorptive cathodic stripping voltammograms (AdCSVs) of 2.5 μmol L⁻¹ progesterone recorded in 0.1 M Na-PBS at unmodified GCE (black), ex situ prepared bismuth film electrode (BiFE) (green), in situ prepared BiFE (blue) and at nanostructured BiFE (red) using accumulation potential of −1.0 V and accumulation time of 120 s.

Figure 3

AdCSVs of 5.0 μmol L⁻¹ progesterone recorded at nsBiFE using accumulation times of 0 s (black), 30 s (green), 60 s (red), 90 s (dark green), 120 s (light blue) and 150 s (blue) (A), and AdCSVs of 2.0 μmol L⁻¹ progesterone recorded at nsBiFE using accumulation potentials of −0.6 V (black), −0.8 V (red), −1.0 V (blue), −1.2 V (green), and −1.4 V (light blue) (B). Other conditions are as in Figure 2.

Figure 4

The effect of interfering species upon the signal of 0.5 μmol L⁻¹ progesterone (P4); 50.0 μmol L⁻¹ uric acid (UA), 50.0 μmol L⁻¹ ascorbic acid (AA), 1.0 μmol L⁻¹ testosterone (TE), 1.0 μmol L⁻¹ 17-β-estradiol (ES) and 2.5 μmol L⁻¹ cholesterol (CH).

Figure 5

AdCSVs for successive additions of progesterone in 0.1 μmol L⁻¹ steps together with background response obtained at nsBiFE using accumulation potential of −0.8 V for 60 s (A) and corresponding calibration plot (B). Other conditions are as in Figure 2.