Development of a Novel Electrochemical Sensor Based on Gold Nanoparticle-Modified Carbon-Paste Electrode for the Detection of Congo Red Dye.

In this study, gold nanoparticles (AuNPs) were electrodeposited on samples of a carbon-paste electrode (CPE) with different thicknesses. The prepared AuNPs were characterized using different analysis techniques, such as FTIR, UV-Vis, SEM, EDX, TEM images, and XRD analysis. The fabricated modified electrode AuNPs/CPE was used for the sensitive detection of Congo red (CR) dye. Electrochemical sensing was conducted using square-wave voltammetry (SWV) in a 0.1 M acetate buffer solution at pH 6.5. The proposed sensor exhibited high efficiency for the electrochemical determination of CR dye with high selectivity and sensitivity and a low detection limit of 0.07 µM in the concentration range of 1-30 µM and 0.7 µM in the concentration range of 50-200 µM. The practical application of the AuNPs/CPE was verified by detecting CR dye in various real samples involving jelly, candy, wastewater, and tap water. The calculated recoveries (88-106%) were within the acceptable range.

Electrochemical Performance of Biocompatible TiC Films Deposited through Nonreactive RF Magnetron Sputtering for Neural Interfacing.

The efficacy of neural electrode stimulation and recording hinges significantly on the choice of a neural electrode interface material. Transition metal carbides (TMCs), particularly titanium carbide (TiC), have demonstrated exceptional chemical stability and high electrical conductivity. Yet, the fabrication of TiC thin films and their potential application as neural electrode interfaces remains relatively unexplored. Herein, we present a systematic examination of TiC thin films synthesized through nonreactive radio frequency (RF) magnetron sputtering. TiC films were optimized toward high areal capacitance, low impedance, and stable electrochemical cyclability. We varied the RF power and deposition pressure to pinpoint the optimal properties, focusing on the deposition rate, surface roughness, crystallinity, and elemental composition to achieve high areal capacitance and low impedance. The best-performing TiC film showed an areal capacitance of 475 µF/cm2 with a capacitance retention of 93% after 5000 cycles. In addition, the electrochemical performance of the optimum film under varying scanning rates demonstrated a stable electrochemical performance even under dynamic and fast-changing stimulation conditions. Furthermore, the in vitro cell culture for 3 weeks revealed excellent biocompatibility, promoting cell growth compared with a control substrate. This work presents a novel contribution, highlighting the potential of sputtered TiC thin films as robust neural electrode interface materials.

Comparative Evaluation of Anticorrosive Properties of Mahaleb Seed Extract on Carbon Steel in Two Acidic Solutions.

Aqueous extract solution of Mahaleb seed (ASMS) was prepared using a simple and safe method. ASMS was tested to examine its potential to act as a green corrosion inhibitor for preventing the dissolution of Carbon steel in highly concentrated corrosive 2 M H2SO4 and 2 M H3PO4 using an electrochemical polarization Tafel plot and electrochemical impedance spectroscopy. ASMS provided a slight increase in the inhibition efficiency of H3PO4 (89%) compared with H2SO4 (86%). Fourier transform infrared spectroscopy (FTIR) and electronic scanning microscopy (SEM) were used to prove that adsorption of ASMS occurred on the metal surface. The thermodynamic adsorption and thermodynamic activation parameters were calculated at a range of concentrations and temperatures. The physisorption of ASMS followed the Langmuir adsorption isotherm (R2 = 0.98). Finally, the role of ASMS as a protection mechanism was discussed.

Synthesis, characterization, and anti-corrosion properties of an 8-hydroxyquinoline derivative.

A new 8-hydroxyquinoline derivative, namely 1,3-bis(quinoline-8-dimethylformamide) propane (BQYP), was synthesized and characterized by different spectral methods, such as 1H NMR, 13C NMR, and FTIR spectra. The anticorrosive properties of the BQYP molecule against the corrosion of mild steel were tested in 2 M Η2SO4 acid with a varied range of concentrations (0.05-1 mM) at different temperatures using the electrochemical technique. It was clear that adsorption acted according to Langmuir's relationship. The inhibition effect improved with increases in concentration of inhibitor (~91% for 1 mM at 298 °K) and was reduced with increasing temperature. Finally, the density functional theory (DFT), with bases set according to the B3LYP/6-311+G (d,p) level, was used for calculating the quantum parameter to explain the effect of the electronic structure of the BQYP molecule on providing the experimental findings.