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A novel voltammetric sensor for the determination of p-nitrophenol has been developed using carbon paste electrode (CPE) modified by metallic palladium (Pd) supported onto natural phosphate (NP). The proposed protocol demonstrates the successful application of palladium compounds in the electrochemical determination of p-nitrophenol (p-NP) in acetate buffer (pH 4.7). Indeed, the palladium displayed a strong catalytic action towards p-nitrophenol reduction. Electrochemical methods including square wave voltammetry (SWV) and chronoamperometry have been used to evaluate the electrochemical behaviour of the palladium towards the catalytic reduction of p-NP. In addition, the proposed electrode was able to catalyse and visualise the intermediate reaction of the nitro group reduction to nitroso group. [ABSTRACT FROM AUTHOR]

Ciprofloxacin (CIPRO) is a second-line antibiotic that belongs to the fluoroquinolone class. Over the years, the consumption of fluoroquinolones has increased exponentially due to their efficacy in treating several common infections. However, the increase in its residues can endanger human health and ecosystems, which requires its monitoring through the development of sophisticated technologies. In this study, a novel sensor for highly selective and rapid detection of CIPRO is fabricated. A facile strategy was employed to fabricate the electrode by impregnation of clay mineral on carbon paste electrode (Clay/CPE). The morphological features of the provided sensor were characterized by means of X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Moreover, the electrochemical characterization of the Clay/CPE was performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with unmodified electrode, the oxidation peak current of CIPRO greatly increased at Clay/CPE indicating the excellent ability to promote electron transfer. Electrochemical measurements have been carried out using differential pulse voltammetry (DPV). Under optimized experimental conditions, the oxidation peak current was linear to the concentration of CIPRO in the range from 2.0 × 10− 7 to 5.0 × 10− 5 mol/L (r2 = 0.98) with a detection limit of 4.6 × 10− 8 mol/L (3 × σ/P). The practical applicability of the as prepared sensor was tested in the spiked human urine and pharmaceutical tablets with good recoveries. The work presented herein was significant as it can serve as tools for the analysis of antibiotics in wastewaters prior to being discharged into the environment since this kind of antibiotics can cause bacterial and genetic resistance in microbial populations present in water bodies, which can negatively affect human health. [Display omitted] • Simple and cost-effective synthesis of clay microparticles for an electrochemical application. • The synthesized clay microparticles were characterized using XRD and FT-IR spectroscopy. • Clay microparticles was used to enhance the performances of CPE toward CIPRO electro-oxidation. • Clay/CPE has been successfully applied for electrochemical detection of CIPRO in tablets and urine samples. [ABSTRACT FROM AUTHOR]

In this work, the authors present an activated carbon modified carbon paste electrode that has superior electrocatalytic activity for the electro-oxidation of dopamine (DA), paracetamol (PCT) and salicylic acid (SA). This excellent electrochemical performance was referred to the porous structure of activated carbon, surface functional groups existing in activated carbon surface and the electron donor–acceptor complex mechanism assumes that the aromatic rings of the drugs act as the electron acceptors. However, the reaction mechanisms of the corresponding electrode were studied in detail in this article. Additionally, under the optimized experimental conditions, DA, SA and PCT exhibit a linear response over the range of 0.1–1000.0 μmol L−1, with the low detection limits of 0.0313 μmol L−1, 0.0282 μmol L−1 and 0.0487 μmol L−1 for DA, PCT and SA, respectively. Furthermore, the AC-CPE showed a high sensitivity, good reproducibility and high stability. The proposed method was applied successfully for the detection of DA, PCT and SA in human blood and pharmaceutical formulations with satisfactory recovery. Image 1027 • A sensitive electrochemical sensor of DA, PCT and SA was successfully developed. • AC/CPE shows good electrocatalytic performance for simultaneous detecting drugs. • Proposed sensor exhibited good reproducibility, stability and low detection limit. • Developed method was satisfactorily applied to analyze the drugs in real samples. [ABSTRACT FROM AUTHOR]