Masoud Taleb; Irina Hussainova; Roman Ivanov; Iwona Jasiuk
Abstract
The present study reports the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in 0.1 M phosphate buffer solution (pH = 7.0) using a novel electrode material prepared from oxide ceramic nanofibers by applying a single step chemical vapor deposition method. Electron-transfer ...
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The present study reports the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in 0.1 M phosphate buffer solution (pH = 7.0) using a novel electrode material prepared from oxide ceramic nanofibers by applying a single step chemical vapor deposition method. Electron-transfer kinetics at the electrode/solution interface was studied by standard redox reaction of 5 mM Fe(CN)6 3-/4- in 1 M KCl. Electrochemical and sensing measurements such as cyclic voltammetry and differential pulse voltammetry were performed to detect DA and UA in the presence of AA. The developed electrode was shown to separate the overlapping voltammetric responses of three analytes into the individual voltammetric peaks, totally eliminate the interference from AA, and distinguish DA from UA. Linear relationship was observed between current intensities and concentrations of all three compounds, and the limits of detection (LOD) were reached 0.57 µM, 0.77 µM and 0.84 µM for DA, UA and AA, respectively. The electrode of graphenated nanofibers displayed a very good reproducibility and stability, and was successfully tested for detection of DA, UA and AA in real urine samples.
Swaroop Kumaraswamy; Gangadhar Babaladimath; Vishalakshi Badalamoole; Somashekarappa H Mallaiah
Abstract
In the present work, the synthesis of ZnO/PVA hydrogel nanocomposites was carried out using the gamma irradiation technique. The ZnO nanoparticles were synthesized using co-precipitation method and dispersed in the PVA solution. To prepare the ZnO/PVA hydrogel nanocomposites, the mixture was exposed ...
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In the present work, the synthesis of ZnO/PVA hydrogel nanocomposites was carried out using the gamma irradiation technique. The ZnO nanoparticles were synthesized using co-precipitation method and dispersed in the PVA solution. To prepare the ZnO/PVA hydrogel nanocomposites, the mixture was exposed to gamma irradiation dose of 25 kGy. The formation of ZnO nanoparticles in PVA matrix was confirmed using the powder X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and the UV-Visible Spectrophotometer (UV). The surface morphology of the hydrogels was studied using the Field Emission Scanning Electron Microscopy (FESEM). The swelling ratio and equilibrium degree of swelling (% EDS) were evaluated and there was drastic reduction in swelling and % EDS with the addition of ZnO nanoparticles to the PVA mixture. The l-ascorbic acid was loaded to the hydrogels and the release data was monitored by the absorption wavelength at 252 nm using UV. The drug release data was fitted to zero order, first order, Higuchi’s model, and Korsmeyer-Peppas’s model for the detailed analysis. The results suggest that ascorbic acid release from the hydrogel matrix follows the non-Fickian mechanism.
Ajit Kumar Sharma;Ajay Kumar Mishra
Abstract
In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar ...
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In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar condition of concentration of styrene and chitosan, 148% grafting was observed with potassium persulphate (K2S2O8)/ascorbic acid as redox initiator and atmospheric oxygen as co-catalyst in 1 h using conventional method at 35 o C. Microwave synthesized Ch-g-sty copolymer was characterized by Fourier transform-Infrared (FTIR) spectroscopy, thermo gravimetric analysis (TGA), X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM). Maximum grafting was optimized by varying the microwave power, exposure time and styrene/chitosan concentration. Ch-g-sty copolymer was found to be more efficient for Cr(VI) removal as compare to conventionally and parent chitosan in aqueous solution. Sorption of Cr(VI) was depending upon pH and concentration, with pH=3 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 526.3 mg/g, 312.5 mg/g and 166.7 mg/g for Ch-g-sty copolymer, conventional (thermostatic water bath) method and parent chitosan respectively.
Ajit Kumar Sharma;Ajay Kumar Mishra
Abstract
In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar ...
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In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar condition of concentration of styrene and chitosan, 148% grafting was observed with potassium persulphate (K2S2O8)/ascorbic acid as redox initiator and atmospheric oxygen as co-catalyst in 1 h using conventional method at 35 o C. Microwave synthesized Ch-g-sty copolymer was characterized by Fourier transform-Infrared (FTIR) spectroscopy, thermo gravimetric analysis (TGA), X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM). Maximum grafting was optimized by varying the microwave power, exposure time and styrene/chitosan concentration. Ch-g-sty copolymer was found to be more efficient for Cr(VI) removal as compare to conventionally and parent chitosan in aqueous solution. Sorption of Cr(VI) was depending upon pH and concentration, with pH=3 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 526.3 mg/g, 312.5 mg/g and 166.7 mg/g for Ch-g-sty copolymer, conventional (thermostatic water bath) method and parent chitosan respectively.
