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An electrochemical sensor for paracetamol (PC) based on the hexacyanoferate(III) intercalated Ni−Al layered double hydroxide (Ni−Al−HCF) was presented. The as-prepared LDH structurally and morphologically was characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform IR. Electrochemical studies revealed that Ni−Al−HCF film modified glassy carbon (GC) electrode exhibited remarkable electrocatalytic activity toward the oxidation of paracetamol. The electrochemical behavior of PC on the Ni−Al−HCF film was investigated in detail. Under optimum experimental conditions, the electrocatalytic response of the modified GC electrode was linear in the PC concentration range 3×10−6−-1.5×10−3 mol L−1, with a detection limit of 8×10−7 mol L−1 (S/N=3), using hydrodynamic amperometry. In addition, the modified electrode exhibited good reproducibility, long-term stability and anti-interference property. The fabricated sensor was successfully applied to determination of PC in various pharmaceutical preparations such as tablets, oral solution, and oral drops. Finally, the method was validated by the analysis of paracetamol spiked human serum samples, and good recoveries were obtained in the range of 99.2-103 %. [ABSTRACT FROM AUTHOR]

Copolymers of poly (2-hydroxyethyl methacrylate)-graft-polyaniline (PHEMA-g-PANI) were synthesized by atom-transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate using polyaniline macro-initiators. The macro-initiators were synthesized by the reaction of amine nitrogens of polyaniline with chloroacetyl choloride. The obtained polymers were characterized by FT-IR and1H NMR spectroscopies. Uniform nanofibers consisting of blends of PHEMA-g-PANI copolymers and polycaprolactone (PCL) were prepared using an electrospinning technique. SEM was used to investigate the morphology of nanofibers produced from PHEMA-g-PANI copolymers and PCL blends. The cyclic voltammetry measurement of blends confirmed the preparation of electroactive nanofibers. [ABSTRACT FROM PUBLISHER]

In this paper, an electrochemical application of bismuth film modified glassy carbon electrode for azo-colorants determination was investigated. Bismuth-film electrode (BiFE) was prepared by ex-situ depositing of bismuth onto glassy carbon electrode. The plating potential was −0.78 V ( vs. SCE) in a solution of 0.15 mg mL Bi(III) and 0.05 mg mL KBr for 180 s. In the next step, a thin film of chitosan was deposited on the surface of bismuth modified glassy carbon electrode, thus the bismuth-chitosan thin film modified glassy carbon electrode (Bi-CHIT/GCE) was fabricated and compared with bare GCE and bismuth modified GCE. Azo-colorants such as Sunset Yellow and Carmoisine were determined on these electrodes by differential pulse voltammetry. Due to overlapping peaks of Sunset Yellow and Carmoisine, simultaneous determination of them is not possible, so net analyte signal standard addition method (NASSAM) was used for this determination. The results showed that coated chitosan can enhance the bismuth film sensitivity, improve the mechanical stability without caused contamination of surface electrode. The Bi-CHIT/GC electrode behaved linearly to Sunset Yellow and Carmoisine in the concentration range of 5×10 to 2.38×10 M and 1×10 to 0.41×10 M with a detection limit of 10 µM (4.52 µg mL) and 10 µM (5.47 µg mL), respectively [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A differential pulse polarography (DPP) for the simultaneous determination of 2-nitrophenol and 4-nitrophenol was proposed. It was found that under optimum experimental conditions (pH = 5, scan rate = 5 mV/s, pulse amplitude = −50 mV), 2-nitrophenol and 4-nitrophenol had well-defined polarographic reduction waves with peak potentials at −317 and −406 mV, respectively. In the mixture of two compounds overlapping polarographic peaks were observed. In this study, support vector regression (SVR) was applied to resolve the overlapped polarograms. Furthermore, a comparison was made between the performance of SVR and partial least square (PLS) on data set. The results demonstrated that SVR is a better well-performing alternative for the analysis and modeling of DPP data than the commonly applied PLS technique. The proposed method was used for the determination of 2-nitrophenol and 4-nitrophenol in industrial waste water. [ABSTRACT FROM AUTHOR]

The Ni-Co nanoparticles with various Ni/Co ratios are immobilized on a Ni foam (NF) template, coated with reduced graphene oxides (rGO), and used as a novel noble-metal-free anode electrocatalyst for enhanced performance direct borohydride fuel cells. The electrochemical active surface area (EASA) of Ni 50 Co 50 /rGO/NF (1515 cm2) catalyst is 45.5 times larger than NF (33.3 cm2). A comprehensive study of direct borohydride-hydrogen peroxide fuel cell (DBHPFC) by Pt/C (0.5 mg cm−2) as a cathode and Ni 50 -Co 50 /rGO/NF as an anode is accomplished, so an open-circuit potential (OCP) of 1.90 V and the maximum power density of 309 mW cm−2 is obtained at 60 ◦C. These results show that electrocatalyst Ni 50 Co 50 /rGO/NF is a suitable candidate for use as an electrocatalyst in DBHPFC due to its low cost, ease of synthesis, excellent structural stability, and high catalytic performance. [Display omitted] • Ni-Co/rGO/NF is a binder-free anode catalyst for direct borohydride fuel cells. • Ni 50 -Co 50 /rGO/NF exhibited the highest power density (309mWcm−2). • The electrochemical active surface area of Ni 50 -Co 50 /rGO/NF catalyst is 1515 cm2. • Ni-Co/rGO/NF is a good candidate for direct borohydride fuel cells with low-cost. [ABSTRACT FROM AUTHOR]

Solubility of anthracene in binary and ternary solvent systems was modeled by artificial neural networks (ANNs) technique. The results obtained using the ANN method indicated that the solubility of anthracene in mixed solvents could be calculated using the mole fraction solubilities in pure solvents, mole/volume fraction of solvents and solvent''s solubility parameters. The topology of neural network was optimized empirically and optimum topology was a 6-6-1 architecture for binary and 9-6-1 for ternary mixtures. The solubility of anthracene in mixed solvents was estimated by means of ANN and the predicted solubility was compared with experimental solubility data. The overall absolute percentage mean deviation (OPMD) for trained ANNs using all data points in 25 binary and 30 ternary solvent systems were 0.16 and 0.20%, respectively. A minimum number of data points from binary and ternary solvents have been employed to train the ANN and solubility at other solvent compositions has been predicted. The OPMD obtained for solubility in binary and ternary solvents were 0.67 and 0.27%, respectively. The trained network with 25 binary data sets was applied to predict the solubility in 16 other binary solvent systems and the OPMD obtained is 15.32%. The results of ANNs were also compared with similar numerical analyses carried out using multiple linear regression models and found that the ANN method is generally promising more accurate calculations. [Copyright &y& Elsevier]

The ever-expanding human societies on the one hand and the diminishing fossil fuel resources on the other have driven man to find a suitable, cheap, clean, and accessible source of energy. Water splitting is a good solution to this crisis. Because of the slow kinetics of water oxidation reaction, it is important to select efficient and durable electrocatalysts to improve the reaction kinetics. In this research, α-MnO 2 /FeCo-LDH catalysts on nickel foam were developed for water oxidation, which exhibited good catalytic performance and stability in a 0.1 M KOH solution. The electrocatalysts were synthesized by hydrothermal methods and characterized by XRD, FTIR, Raman, SEM, TEM, EDS, and MAP techniques. The proposed modified electrode has large exchange current, low overpotential, and small Tafel slope. Here, only an overpotential of 210 mV is required to achieve a current density of 5 mA cm 2 with a Tafel slope of 70.4 mV dec -1 in an alkaline solution., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

In this work, a novel strategy was introduced to develop a non-enzymatic hydrogen peroxide (H 2 O 2 ) sensor based on rifampicin (RIF) electrodeposited on a polyvinylpyrrolidone (PVP)-capped CdSe quantum dot (CdSeQD), CoFe 2 O 4 magnetic nanoparticle-modified glassy carbon electrode (CoFe 2 O 4 @CdSeQDs/RIF/GCE). CoFe 2 O 4 @CdSeQD magnetic nanocomposite (CoFe 2 O 4 @CdSeQD MNCs) was synthesized by a chemical co-precipitation method and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). To prepare the non-enzymatic H 2 O 2 sensor, firstly, the glassy carbon electrode surface was modified by dropping 10 μL of 5 mg mL -1 CoFe 2 O 4 @CdSeQD MNCs. Then, rifampicin was electrodeposited on the activated CoFe 2 O 4 @CdSeQDs/GCE by applying a potential of - 0.7 V for 400 s in pH 2.0 phosphate buffer containing 190 μM of rifampicin. Cyclic voltammetry and electrochemical impedance spectroscopy was used to investigate the electrochemical behavior of this sensor and was used for the reduction of H 2 O 2 . Construction of the calibration plot for H 2 O 2 was performed using an amperometric method (- 0.2 V vs. Ag/AgCl) at the modified electrode. Two linearity ranges were obtained from 7 to 145 μM and 145 μM to 1.43 mM with sensitivities of 143.01 μA mM -1 and 28.67 μA mM -1 for the first and second linearity ranges, respectively. The detection limit was obtained as 0.38 μM (S/N = 3). Finally, the reliability of the nanosensor was confirmed with real sample analysis in different beverages such as juice and milk with satisfactory recovery results.

A copper hexacyanoferrate nanostructure was prepared on the surface of a disposable pencil graphite electrode. The copper hexacyanoferrate nanostructures showed a pair of symmetric voltammetric peaks at 0.67 V/SCE. An electrochemical comparative characterization between copper hexacyanoferrate nano and bulk structures was presented. The transfer coefficient (α) and apparent charge rate constant (Ks) were evaluated for each of copper hexacyanoferrate nano and bulk structures. The resulting electrode exhibits an excellent electrocatalytic activity for the oxidation of ceftriaxone sodium. Cyclic voltammetry and chronoamperometry were employed to characterize the response to ceftriaxone sodium that changes linearly in the concentration range from 2 to 72 μM, with a detection limit of 0.54 μM (at a signal to noise ratio of 3). Typical features of the sensor include low cost, simple preparation, fast response, good stability, selectivity, and reproducibility. It was applied to the determination of ceftriaxone sodium in pharmaceutical samples. All results obtained were compared to the recommended procedure by British Pharmacopeia.