No abstract

A glassy carbon electrode is modified with multi-walled carbon nanotubes, Au nanoparticles, and poly-L-serine. Characterization of the modified electrode by FESEM, EDS, cyclic voltammetry, and electrochemical impedance spectroscopy showed the presence of a conductive nanocomposite on the electrode surface. Compared to an unmodified electrode, the oxidation peak current of progesterone increases at the modified electrode, significantly, while the peak potential shifts to less positive values. The electrode ingredients and experimental conditions are optimized for sensitive determination of progesterone. A linear calibration curve is obtained in physiological pH 7.4 in a wide concentration range of 0.001-2.0 μM (0.31 to 636 ng ml −1 ), and limit of detection of 0.2 nM (0.063 ng ml −1 ) based on S/N = 3. The modified electrode is used for the determination of progesterone in human blood serum samples of men and women, and pharmaceutical preparations, successfully. Good accuracy (relative errors less than 4%) and precision (relative standard deviation, RSD% of 3 replicate measurements were less than 2.67%) were calculated from the experimental results of real samples.