Sphere-like Ni3S4/NiS2/MoOx composite modified glassy carbon electrode for the electrocatalytic determination of d-penicillamine

A Dopamine Detection Sensor Based on Au-Decorated NiS2 and Its Medical Application

This article reports a simple hydrothermal method for synthesizing nickel disulfide (NiS2) on the surface of fluorine-doped tin oxide (FTO) glass, followed by the deposition of 5 nm Au nanoparticles on the electrode surface by physical vapor deposition. This process ensures the uniform distribution of Au nanoparticles on the NiS2 surface to enhance its conductivity. Finally, an Au@NiS2-FTO electrochemical biosensor is obtained for the detection of dopamine (DA). The composite material is characterized using transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the sensor are investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and time current curves in a 0.1 M PBS solution (pH = 7.3). In the detection of DA, Au@NiS2-FTO exhibits a wide linear detection range (0.1~1000 μM), low detection limit (1 nM), and fast response time (0.1 s). After the addition of interfering substances, such as glucose, L-ascorbic acid, uric acid, CaCl2, NaCl, and KCl, the electrode potential remains relatively unchanged, demonstrating its strong anti-interference capability. It also demonstrates strong sensitivity and reproducibility. The obtained Au@NiS2-FTO provides a simple and easy-to-operate example for constructing nanometer catalysts with enzyme-like properties. These results provide a promising method utilizing Au coating to enhance the conductivity of transition metal sulfides.

Construction and Application of an Electrochemical Sensor for Determination of D-Penicillamine Based on Modified Carbon Paste Electrode

D-penicillamine (D-PA) is a sulfur-containing drug that has been used for various health conditions. However, like any medication, overdosing on D-PA can have adverse effects and may require additional treatment. Therefore, developing simple and sensitive methods for sensing D-PA can play a crucial role in improving its efficacy and reducing its side effects. Sensing technologies, such as electrochemical sensors, can enable accurate and real-time measurement of D-PA concentrations. In this work, we developed a novel electrochemical sensor for detecting D-PA by modifying a carbon paste electrode (CPE) with a multi-walled carbon nanotube-Co3O4 nanocomposite, benzoyl-ferrocene (BF), and ionic liquid (IL) (MWCNT-Co3O4/BF/ILCPE). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CHA) were employed to explore the electrochemical response of D-PA on the developed sensor, the results of which verified a commendable electrochemical performance towards D-PA. Under optimized conditions, the developed sensor demonstrated a rapid response to D-PA with a linear dynamic range of 0.05 μM-100.0 μM, a low detection limit of 0.015 μM, and a considerable sensitivity of 0.179 μA μM-1. Also, the repeatability, stability, and reproducibility of the MWCNT-Co3O4/BF/ILCPE sensor were studied and showed good characteristics. In addition, the detection of D-PA in pharmaceutical and biological matrices yielded satisfactory recoveries and relative standard deviation (RSD) values.

Development of Polydiphenylamine@Electrochemically Reduced Graphene Oxide Electrode for the D-Penicillamine Sensor from Human Blood Serum Samples Using Amperometry

D-penicillamine (PA) is a sulfur group-containing drug prescribed for various health issues, but overdoses have adverse effects. Therefore, regular, selective, and sensitive sensing is essential to reduce the need for further treatment. In this study, diphenylamine (DPA) was electropolymerized in an aqueous acidic medium. The PA detection sensitivity, selectivity, and limit of detection were enhanced by electropolymerizing DPA on an electrochemically reduced graphene oxide (ERGO)/glassy carbon (GC) surface. The formation of p-DPA and ERGO was investigated using various techniques. The as-prepared p-DPA@ERGO/GC revealed the excellent redox-active (N-C to N=C) sites of p-DPA. The p-DPA@ERGO/GC electrode exhibited excellent electrochemical sensing ability towards PA determination because of the presence of the -NH-functional moiety and effective interactions with the -SH group of PA. The p-DPA@ERGO/GC exhibited a high surface coverage of 9.23 × 10^-12 mol cm^-2. The polymer-modified p-DPA@ERGO/GC electrode revealed the amperometric determination of PA concentration from the 1.4 to 541 μM wide range and the detection limit of 0.10 μM. The real-time feasibility of the developed p-DPA@ERGO/GC electrode was tested with a realistic PA finding in human blood serum samples and yielded a good recovery of 97.5-101.0%, confirming the potential suitability in bio-clinical applications.