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A new highly sensitive and selective electrochemical levofloxacin sensor based on co‐polymer‐carbon nanotube composite electrode was developed. Taurine and Glutathione were electrochemically co‐polymerized on multiwalled carbon nanotubes modified glassy carbon electrode (Poly(TAU‐GSH)/CNT/GCE) and used as a levofloxacin sensor in pH 6 phosphate buffer solution. The new composite electrode surfaces were characterized by scanning electron microscopy, atomic force microscopy and electrochemical impedance spectroscopy. Under the optimized conditions, two linear segments were obtained for increasing LEV concentrations between 20 nmol L−1‐1 μmol L−1 and 1.5 μmol L−1‐55 μmol L−1 LEV with a detection limit of 9 nmol L−1 using amperometry. Poly(TAU‐GSH)/CNT/GCE exhibited high sensitivity, selectivity with good stability. The new sensor was employed for real samples of LEV tablets and urine. Promising results were obtained with good accuracy which were also in accordance with LC‐MS/MS analysis.

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A system of Pt nanoparticles and poly(ortho‐phenylenediamine) film electrochemically deposited onto a glassy carbon electrode (GCE/PoPD/Pt) was fabricated. Scanning electron microscopy, Fourier‐transform infrared spectroscopy, and atomic force microscopy techniques were used to identify the surface characteristics of the composite electrode. The conductive polymers and Pt nanoparticles together resulted in a synergistic effect, and the new formed surface was highly active against polyphenolic structures. Rosmarinic acid (RA) and protocatechuic acid (PCA) are phenolic compounds found in plants, and they are used in many applications, particularly as pharmaceuticals. The GCE/PoPD/Pt was used for the simultaneous determination of RA and PCA in a pH 2.0 H2SO4 solution for the first time. The RA and PCA concentrations were determined using differential pulse voltammetry (DPV) and chronoamperometry. By the amperometry measurement, for RA and PCA, a linear relation was observed in the concentration ranges of 1–55 μmol L−1 and 1–60 μmol L−1, with detection limits of 0.5 μmol L−1 and 0.6 μmol L−1, respectively. In the simultaneous determination with DPV, the detection limits for both RA and PCA were calculated as 0.7 μmol L−1. The GCE/PoPD/Pt was successfully used for the simultaneous determination of RA and PCA in a real sample, and its accuracy was verified by high‐performance liquid chromatography studies.

Ammonia borane is widely used in most areas including fuel cell applications. The present paper describes electrochemical behavior of ammonia borane in alkaline media on the poly(p-aminophenol) film modified with Au and Ag bimetallic nanoparticles. The glassy carbon electrode was firstly covered with polymeric film electrochemically and then, Au, Ag, and Au–Ag nanoparticles were deposited on the polymeric film, respectively. The surface morphology and chemical composition of these electrodes were examined by scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was found that alloyed Au–Ag bimetallic nanoparticles are formed. Electrochemical measurements indicate that the developed electrode modified by Au–Ag bimetallic nanoparticles exhibit the highest electrocatalytic activity for ammonia borane oxidation in alkaline media. The rotating disk electrode voltammetry demonstrates that the developed electrode can catalyze almost six-electron oxidation pathway of ammonia borane. Our results may be attractive for anode materials of ammonia borane fuel cells under alkaline conditions.Graphical Abstract