In the present study, a bimetallic nanostructure of gold-copper (Au-CuNPs) was decorated on the surface of porous silicon (PSi) using an easy galvanic replacement reaction between metal ions and PSi in the presence of 0.1 M hydrofluoric acid solution. The morphology and structures of the Au-CuNPs@PSi nanocomposite were characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) energy-dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV) techniques. Then, prepared nanocomposite was used as a modifier in screen-printed carbon electrode (SPCE) for the highly sensitive simultaneous determination of codeine (COD) and acetaminophen (ACE). The combination of PSi and metals nanoparticles provide a porous and high surface area with excellent electrical conductivity which leads to reduce the peak potentials and enhance the oxidation peak currents of COD and ACE at the surface of the Au-CuNPs@PSi/SPCE nanosensor. The dynamic linear ranges were obtained from 0.06 to 0.6 µM for both COD and ACE and the detection limits (3.0 S/N) estimated 0.35 µM for COD and 0.30 µM for ACE, respectively. Moreover, recovery tests were carried out in real samples such as urine, human blood plasma, and tablets.
In this work, a screen‐printed carbon electrode (SPCE) was modified with a cobalt/porous silicon (Co@PSi) nanocomposite powder to develop a nonenzymatic sensor for the detection of hydrogen peroxide. The Co@PSi nanocomposite was synthesized through the chemical reaction between silicon powder in a HF/HNO3 solution and cobalt cations. In this process, cobalt nanoparticles were anchored on the porous silicon. The structure and morphology of the synthesized nanocomposite were investigated by X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray photoemission spectroscopy, energy dispersive X‐ray spectroscopy, and field‐emission scanning electron microscopy. The constructed nonenzymatic, screen‐printed sensors based on the Co@PSi nanocomposite showed perfect electrocatalytic oxidation response to hydrogen peroxide over the range 1–170 and 170–3,770 μmol/L with the limit of detection of 0.8 μmol/L. In addition, the Co@PSi‐SPCE sensor exhibited good selectivity for the determination of H2O2 in the presence of common interfering species including glucose, ascorbic acid, uric acid, dopamine, nitrate, and nitrite ions. The constructed electrochemical sensor was successfully used for the determination of H2O2 in real samples.
In this work, a new nanocomposite as silver nanoparticles (AgNPs)@ porous silicon (PSi) was synthesised through a simple galvanic displacement reaction between silver ions and silicon in the presence of hydrofluoric acid. The as-prepared nanocomposites were characterised via field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and electrochemical methods. Since the nanocomposite showed a greatly enhanced electrocatalytic activity towards the glucose oxidation in alkaline solution, Ag nanoparticles supported on PSi flour were used as a performance modifier in the construction of a new amperometric glucose screen-printed carbon electrode. The enzymatic free glucose sensor based on AgNPs@PSi exhibited a wide linear dynamic range of 1 × 10 −6-45.7 × 10 −3 M, with a detection limit of 6 × 10 −7 M at a signal-to-noise ratio of 3, and fast response (<3 s). Also, the response of the proposed sensor was selective towards glucose in the presence of common species such as ascorbic acid, dopamine, uric acid and Cl − ions. Finally, the sensor was successfully applied to determine glucose in human serum samples.
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