Gold nanoparticles/f-MWCNT nanocomposites modified glassy carbon paste electrode as a novel voltammetric sensor for the determination of cyproterone acetate in pharmaceutical and human body fluids

In this work, a novel voltammetric sensor was fabricated by the decoration of carboxylated multi-walled carbon nanotubes (f-MWCNT) with gold nanoparticles (AuNPs) using glassy carbon paste (GCP) as a cross linker (AuNPs/f-MWCNT/GCPE) for determination of cyproterone acetate (CPA) drug. Electrochemical behavior and the surface characterization of the AuNPs/f-MWCNT/GCPE were investigated using scanning electron microscopy (SEM), cyclic voltammetry (CV) and square wave voltammetry (SWV). The modified electrode showed a distinctive cathodic response towards CPA using SWV in phosphate buffer medium (pH 5.0) with a considerable enhancement peak current (42 μA) compared to the bare GCPE (4 μA). Under the optimum conditions, the SWV peak current of CPA increased linearly with its concentration at the range of 9.90 × 10⁻⁸ to 1.15 × 10^-5 M with a detection limit of 1.66 × 10⁻⁸ M (6.92 ng/mL) and calculated sensitivity of 92.93 μA μM^–1 cm^–2. The modified electrode displayed anti-interference ability against the physiological common interferents (i.e. ascorbic acid, uric acid, alanine, cysteine, glucose, citric acid, uracil, and serine). Furthermore, the fabricated electrochemical sensor displays a high sensitivity, good reproducibility, and long-term stability and it was effectively applied for the determination of CPA in pharmaceutical products (Androcur) and in human blood serum and urine samples.