[en] A novel nanomaterial-based voltammetric sensor has been developed for use a highly sensitive tool for the simultaneous determination of captopril (CA), acetaminophen (AC), tyrosine (TY) and hydrochlorothiazide (HCTZ). The device is based on the application of NiO/CNTs and (2-(3,4-dihydroxyphenethyl)isoindoline-1,3-dione) (DPID) to modify carbon paste electrodes. The NiO/CNTs nanocomposite was synthesized through a direct chemical precipitation approach and was characterized with X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The NiO/CNTs/DPID/CPEs were found to facilitate the analysis of CA, AC, TY and HCTZ in the concentration ranges of 0.07–200.0, 0.8–550.0, 5.0–750.0 and 10.0–600.0 μM with the respective detection limits of 9.0 nM, 0.3 μM, 1.0 μM and 5.0 μM. The developed NiO/CNTs/DPID/CPEs were used for the determination of the mentioned analytes in pharmaceutical and biological real samples. - Graphical abstract: In this study a novel sensor based on NiO/CNTs and (2-(3,4-dihydroxyphenethyl)isoindoline-1,3-dione) (DPID) modified carbon paste electrode fabricated for simultaneous determination of captopril, acetaminophen, tyrosine and hydrochlorothiazide for the first time. - Highlights: • Fabrication of NiO/CNTs and new catechol derivative modified carbon paste electrode • Good ability of proposed sensor for biological and pharmaceutical analysis • Simultaneous determination captopril, acetaminophen, tyrosine and hydrochlorothiazide

[en] In this study, we prepared a stable covalently bonded ferrocene derivative (ferrocenecarboxaldehyde) over SiO₂–Al₂O₃ mixed-oxide in nanoscale size (Fe ions did not accumulate and were dispersed as Fe metal ion–nanoparticles). SiO₂–Al₂O₃ mixed-oxide was functionalized with 3-aminopropyl-triethoxysilane group and ferrocenecarboxaldehyde was covalently linked to the organo-functionalized SiO₂–Al₂O₃ mixed-oxide. Fourier transform infrared spectroscopy, UV–Vis, CHN elemental analysis, inductively coupled plasma optical emission spectroscopy (ICP–OES), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), and cyclic voltammetry were used to characterize the synthesized materials. Nitrogen sorption measurements of the modified Si/Al mixed-oxide confirm the presence of the ferrocene molecules attached to the modified Si/Al mixed-oxide. The considerable decrease in the specific surface area clearly indicates functionalization of the surface of the mixed-oxide with ferrocene. The nitrogen and Fe contents of the organometallic-modified Si/Al mixed-oxide (SAPFE) were determined by elemental analysis and ICP–OES, respectively, which were then used to compute the immobilized SAPFE content. SEM and TEM images confirm that the metal particle (Fe ions) size distribution forms a continuum between the minimal (2–5 nm) and the maximal (about 50 nm) diameters. The organo-functionalized SiO₂–Al₂O₃ mixed-oxide was used as a mediator for the determination of penicillamine at pH 6.0. Under the optimum conditions at pH 6.0, the oxidation peak potential of penicillamine at the modified electrode shifts about 400 mV to less positive value than for the unmodified carbon paste electrode. Differential pulse voltammetry exhibited two wide linear dynamic ranges of 0.06–7.5 and 7.5–140 μmol L⁻¹ penicillamine. The detection limit was found to be 0.01 μmol L⁻¹ penicillamine. Kinetic parameters such as electron transfer coefficient and catalytic reaction rate constant were also determined using the electrochemical approaches. Finally, the modified electrode was used as a novel nanosensor for the determination of penicillamine in real samples such as drug, serum, and urine.

[en] Glutathione (GSH) is an important tripeptide that plays an important role in preventing damage to reactive oxygen species. An electrochemical assay was fabricated for this purpose by modification of a carbon paste electrode (CPE) with bis(1,10-phenanthroline)(1,10-phenanthroline-5,6-dione)nickel(II) hexafluorophosphate (BPPDNi) as new electro-catalyst and Pt:Co nanoparticle (Pt:CO-NPs) as highly conductive mediator. The analyses were performed at a scan rate of 10 mV/s and at a pH value of 7.4. The BPPDNi/Pt:CO-NPs/CPE showed a high sensitivity and good selectivity for electro-catalytic determination of glutathione (GSH) in nano-molar concentration range. In addition, the BPPDNi/Pt:CO-NPs/CPE was used for the determination of glutathione in the presence of doxorubicin (DOX) and tyrosine (Tyr) with three separated oxidation signals ~160 mV, ~385 mV and ~790 mV vs. Ag/AgCl/KCl_sat, respectively. The peak currents of the square wave voltammetric analyses were linearly dependent on glutathione, doxorubicin and tyrosine concentrations in the respective ranges of 0.001–450, 0.5–300 and 1.0–650 μM, with detection limits of 0.5 nM, 0.1 μM and 0.6 μM, respectively.

.

[en] In the present study, trace quantities of copper(II) and zinc(II) ions in natural water, herbal and food samples was separated, preconcentrated and determined by a new nanocomposite. The nanocomposite was prepared by immobilization of diphenylcarbazone on SBA-15 nanoparticles coated with anionic surfactant sodium dodecyl sulfate. In order to investigate the effectiveness and size of the surface, SBA-15 nanoparticles and nanocomposites were analyzed by Brunauer–Emmett–Teller technique, transmission electron microscope, elemental analysis map, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and elemental analysis CHNS. The effective factors such as pH, adsorbent amount, extraction time, eluent concentration and acid recovery volume were investigated and optimized for quantitative determination of Cu(II) and Zn(II) ions. Figures of merit such as precision, accuracy, limit of detection, enhancement factor and enrichment factor were obtained with good results. The linear range of the calibration graph was between 0.5 and 100 ng ${\text{mL}}^{-<!--\; ???\; -->1}$ for Cu(II) and between 1 and 500 ng ${\text{mL}}^{-<!--\; ???\; -->1}$ for Zn(II), and the detection limit was calculated to be 0.21 and $0.93\text{ng}{\text{mL}}^{-<!--\; ???\; -->1}$, respectively. Relative standard deviations of Cu and Zn were calculated to be 1.54 and 1.31%, respectively.

[en] A novel ionic liquid modified NiO/CNTs carbon paste electrode (IL/NiO/CNTCPE) had been fabricated by using hydrophilic ionic liquid 1-methyl-3-butylimidazolium chloride [MBIDZ]Cl as a binder. The cyclic voltammogram showed an irreversible oxidation peak at 0.61 V (vs. Ag/AgCl_sat), which corresponded to the oxidation of morphine. Compared to common carbon paste electrode, the electrochemical response was greatly improved for morphine electrooxidation. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of morphine and diclofenac. Detection limit of morphine was found to be 0.01 μM using square wave voltammetry (SWV) method. The proposed sensor was successfully applied for the determination of morphine in human urine and pharmaceutical samples. - Graphical abstract: Diclofenac as a nonsteroidal anti-inflammatory drug has been shown to decrease morphine consumption after operation in adults. The addition of regular doses of diclofenac may reduce the need for morphine after abdominal surgery. Therefore, in this study we describe a sensitive electrochemical sensor for simultaneous determination of morphine and diclofenac. - Highlights: • Electrochemical behavior of morphine study using modified carbon paste electrode • The sensor resolved the overlap of morphine and diclofenac • This sensor is also used for the determination of morphine in real samples

[en] The eggshell (ES) supported Cu(OH)_2 nanoribbons containing 8 wt.% Cu"2"+ as a novel and heterogeneous catalyst was synthesized by simply adding an aqueous solution of CuSO_4 on the eggshell support at ambient temperature. The nanocomposite system was characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and BET surface area analysis. Also, electrochemical impedance spectroscopy was used as powerful techniques for an electrical conductivity investigation. The loading of copper on the mesoporous supports provides high catalytic activity for the green synthesis of pyrano[4,3-b]pyrans. The reaction proceeds to completion in 5 min with excellent yields of 93–97%. The suggested strategy for synthesis of pyrano[4,3-b]pyrans is very interesting due to application of a green and low cost composite as a heterogeneous catalyst and its simplicity in preparation, short reaction time, high yields without further purification and high reusability without any loss of catalytic activity. - Highlights: • Synthesis and full characterization of ES/Cu(OH)_2 nanocomposite • ES/Cu(OH)_2 characterization with XRD, TGA, FTIR spectra, SEM, TEM and BET • Green and rapid synthesis of pyrano[4,3-b]pyrans in the presence of eggshell supported Cu(OH)_2 nanoribbons • High catalytic activity and reusability of nanocomposite even after three cycles • Investigation of electrical conductivity of nanocatalyst

[en] A carbon paste electrode (CPE) was modified with Pt-Co nanoparticles and 2-(3,4-dihydroxyphenethyl)isoindoline-1,3-dione (3,4-DHPID) and then used for determination of N-acetylcysteine (N-AC) in the presence of paracetamole (PC) and folic acid (FA). The Pt-Co nanoparticles were synthesized by the polyol method and characterized by X-ray diffraction, energy dispersive X-ray analysis and transmission electron microscopy. The modified CPE displays good electrocatalytic activity towards the electrooxidation of N-AC in solution of pH 7.0. It was applied to the determination of N-AC in the presence of PC and FA (with well separated signals peaking at 0.2, 0.55 and 0.86 V vs. Ag/AgCl) by using square wave voltammetry. The peak currents are linearly dependent on the concentrations of N-AC, PC and FA in the respective ranges from 0.07 to 500, 1.0 to 850, and 2.0 to 550 μmol·L⁻¹, with detection limits of 0.009, 0.6 and 0.8 μmol·L⁻¹. The modified CPE was applied to the determination of N-AC, PC and FA in (spiked) pharmaceutical and biological samples. (author)

[en] Recently, attentions to the applications of biotechnology and nanotechnology in the polymer industries have been greater than before. Hybrid nanocomposites containing multi-type of nano structures are widely established, but application of biotechnology for in-situ embedment of nanoparticles in polymer matrix is rarely reported. In this study, poly (ethylene terephthalate) (PET) based ternary bionanocomposites containing modified chitosan (phosphorylated chitosan) and nanosilver particles were prepared by simple eco-friendly method. Chitosan was selected as a biopolymer with respect to the biological activity and compatibility with PET. Phosphorylation of chitosan was achieved in order to introduce the phosphorus moieties as a flame retardant agent in PET matrix by using chemical approach. Also a cost-effective and environmentally friendly method was used for the in-situ fabrication and decoration of silver nanoparticles on to phosphorylated chitosan in PET matrix. Effects of the hybrid system (phosphorylated chitosan and silver nanoparticles) on the morphology, thermal behavior and antibacterial properties of the PET samples were investigated by different methods. The microstructure and homogeneity of the samples were analyzed by studying of dispersion of nanoparticles in PET via scanning electron microscopy. The antibacterial properties of PET nanocomposites can be improved by insertion of silver nanoparticles into the bulk of polymer matrix. Obtained results indicated that the PET/phosphorylated chitosan/silver nanocomposites showed a significantly higher growth inhibition rate compared with the PET and PET/phosphorylated chitosan blend. Also the flame retardant properties of PET nanocomposites were drastically enhanced.

[en] In the present study, a novel 1-butyl-3-methylimidazolium bromide (BmImBr) impregnated chitosan beads were prepared and characterized using different methods, including XRD, FT-IR, EDX, SEM and BET. The FTIR analysis revealed that the BmImBr was successfully conjugated with the chitosan in the beads structure. The prepared beads were used as an efficient sorbent for the fast removal of methylene blue, as cationic dye model, from aqueous solution, whereas just 25 min was required to reach 86% removal efficiency. The increasing of BmImBr amount improved the adsorption performance of prepared beads. Also, it was found that the dye can be higher adsorbed on the beads surface by increasing the sorbent dosage and pH of solution, while the optimum dosage and pH were obtained 3 mg/L and 11, respectively. The kinetic study showed that the MB adsorption onto the CS-BmImBr beads follows the pseudo-fist order model and the intrinsic penetration controls the adsorption process. The properties of prepared chitosan- BmImBr IL conjugation confirmed that it can be exploited as an efficient adsorbent in the wastewater treatment.

[en] Herein, it is aimed to develop a high-performance monolithic adsorbent to be utilized in methyl orange (MO) adsorption. Therefore, amino-functionalized three-dimensional graphene networks (3D-GN_f) fulfilling the requirements of reusability and high capacity have been fabricated via hydrothermal self-assembly approach followed by a double-crosslinking strategy. The potential utilization of 3D-GN_f as an adsorbent for removal MO has been assessed using both batch-adsorption studies and an artificial neural network (ANN) approach. Graphene oxide sheets have been amino-functionalized and cross-linked, by ethylenediamine (EDA) during hydrothermal treatment, following the glutaraldehyde has used as a double-crosslinking agent to facilitate the crosslinking of architecture. The successful fabrication of 3D-GN_f has been confirmed by field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS). Moreover, N₂ adsorption/desorption isotherms have revealed the high specific surface area (1015 m² g⁻¹) with high pore volume (1.054 cm³ g⁻¹) and hierarchical porous structure of 3D-GN_f. The effect of initial concentration, contact time, and temperature on adsorption capacity have been thoroughly studied, and the kinetics, isotherms, and thermodynamics of MO adsorption have been modelled. The MO adsorption has been well defined by the pseudo-second-order kinetic model and Langmuir isotherm model with a monolayer adsorption capacity of 270.27 mg g⁻¹ at 25 $°C$. The thermodynamic findings have revealed MO adsorption has occurred spontaneously with an endothermic process. The Levenberg-Marquardt backpropagation algorithm has been implemented to train the ANN model, which has used the activation functions of tansig and purelin functions at the hidden and output layers, respectively. An optimum ANN model with high-performance metrics (coefficient of determination, R² = 0.9995; mean squared error, MSE = 0.0008) composed of three hidden layers with 5 neurons in each layer was constructed to forecast MO adsorption. The findings have shown that experimental results are consistent with ANN-based data, implying that the suggested ANN model may be used to forecast cationic dye adsorption.