Authors:Zongxue Yu, Yuxi Sun, Wenxian Wei, Lude Lu, and Xin Wang
Orthorhombic structural perovskite NdCrO3 nanocrystals with size of 60 nm were prepared by microemulsion method, and characterized by XRD, TEM, HRTEM, SEM, EDS and
BET. The catalytic effect of the NdCrO3 for thermal decomposition of ammonium perchlorate (AP) was investigated by DSC and TG-MS. The results revealed that the NdCrO3 nanoparticles had effective catalysis on the thermal decomposition of AP. Adding 2% of NdCrO3 nanoparticles to AP decreased the temperature of thermal decomposition by 87° and increased the heat of decomposition from
590 to 1073 J g−1. Gaseous products of thermal decomposition of AP were NH3, H2O, O2, HCl, N2O, NO, NO2 and Cl2. The mechanism of catalytic action was based on the presence of superoxide ion O2− on the surface of NdCrO3, and the difference of thermal decomposition of AP with 2% of NdCrO3 and pure AP was mainly caused by the different extent of oxidation of ammonium.
Authors:K. Pramod, U. K. Ilyas, M. Singh, Y. T. Kamal, S. Ahmad, S. H. Ansari, and J. Ali
High-performance thin-layer chromatography (HPTLC) method for the quantification of eugenol from nanostructured drug delivery systems was successfully developed and validated. The mobile phase consisted of n-hexane:acetone (7:3, v/v), and the densitometric scanning was performed in the absorbance mode at 280 nm. The method was valid with respect to linearity and range, accuracy, precision, specificity, detection limit (DL), and quantitation limit (QL). The linearity of the method was established by a correlation coefficient value of 0.9930 ± 0.0013. The precision was tested by checking intra-day (repeatability) and inter-day (intermediate precision) variations. The method was established to be precise by low relative standard deviation (RSD) values for different concentration of eugenol. The results of the recovery studies of eugenol from preanalyzed samples demonstrated the accuracy of the method. The specificity of the developed method for the analysis of eugenol in the nanoemulsion gel and nanoparticles samples was confirmed by comparing the spectra obtained in standard and sample analysis. The DL and QL were determined to be 31.41 and 95.17 ng band−1, respectively, for the HPTLC method. The forced degradation studies revealed on eugenol established the effectiveness of the developed and validated method. The developed and validated HPTLC method was found to be a stability-indicating one, as indicated by the results of forced degradation studies, for its use during the accelerated stability studies of the nanoemulsion gels and nanoparticles of eugenol.
Authors:Mohammed Kechadi, Mathilde Faure, Bruno Sotta, and Jean Gamby
The real-time monitoring of the adsorption kinetic of antibody onto polyethylene terephthalate (PET) modified with gold nanoparticles (NPs) is performed into a dielectric flow microchannel. The principle is based on the microelectrode–dielectric interface excitation by a modulated voltage excitation through the dielectric layer with high frequency range. The set-up configuration using a homemade current-to-voltage converter has been developed for fast monitoring of biomolecule adsorption without direct electrical contact of microelectrodes with the microchannel flow. The change in the interfacial admittance, related to the output voltage measured through the microchip, during antibody incubation, gives information on the kinetics involved while antibodies are adsorbed at the interface. An example of adsorption on PET modified with gold NPS was taken. Experimental data were fit with the Langmuir equation and a good correlation was obtained with this latter, where the equilibrium constant, K, was found as 1.55 × 108 M−1 with a limit of detection for antibody concentration without depletion equal to 8.25 nM.
devoted to the characterization of elastomer compounds containing NZnO particles. For example, Sahoo and Bhowmick [ 12 ] synthesized rod-shaped ZnO nanoparticles and studied the effect of prepared nanoparticles on cure characteristics besides static and
Authors:Shidi Tang, Yuanfu Deng, and ShuZhong Zhan
Figure 7 shows the transmission electron images of the PbTiO 3 nanoparticles obtained from pyrolysis complex 1 at 773 K for 2 h. It was found that PbTiO 3 powders only consisted of the nano-scale crystallites with the crystalline size of 60–100 nm
Authors:Ferenc Ender, Diána Weiser, Botond Nagy, Csaba László Bencze, Csaba Paizs, Péter Pálovics, and László Poppe
Biotransformation of l-phenylalanine (l-1a) and five unnatural substrates (rac-1b–f) by phenylalanine ammonia-lyase (PAL) was investigated in a novel microfluidic device (Magne-Chip) that comprises microliter volume reaction cells filled with PAL-coated magnetic nanoparticles (MNPs). Experiments proved the excellent reproducibility of enzymecatalyzed biotransformation in the chip and the excellent reusability of the enzyme layer during 14 h continuous measurement (>98% over 7 repetitive measurements with l-1a). The platform also enabled fully automatic multiparameter measurements with a single biocatalyst loading of about 1 mg PAL-MNP. Computational fluid dynamics (CFD) calculations were used to study the flow field in the chambers and the effect of unintended bubble formation. Optimal flow rate for l-1a reaction and specific activities for rac-1b–f under these conditions were determined.
Authors:Ghodratollah Absalan, Morteza Akhond, Elmira Rafatmah, and Yousef Alipour
Gold nanoparticles (AuNPs) and l-cysteine (l-cys), in order, as first and second layer were coated on the surface of a commercial thin-layer chromatography (TLC) plate. This assemble has been used as a new substrate for direct resolution of propranolol enantiomers based on the ordinary TLC technique. The effect of concentrations of the involved chemicals, time periods of the required processes, pH of the sample solutions, as well as the effects of different coating protocols on the resolution of the enantiomers, were investigated in order to find the optimized separation conditions. The results showed that 10.0 mM copper(II) acetate, in 70% ethanol-water adjusted at pH = 6.3, was suitable for being used as the mobile phase. The AuNPs with the average size of 15 nm and l-cys solution with a concentration of 10.0 mM and pH = 8.1 had been chosen for impregnating TLC plates.
Authors:N. Akhtar, Md. Faiyazuddin, G. Mustafa, Y. Sultana, S. Baboota, and J. Ali
Formaldehyde in aquatic products was determined by micellar electrokinetic capillary chromatography (MEKC) after derivatization with 2,4-dinitrophenylhydrazine. Separation was carried out at 25 °C and 25 kV, using a fused silica capillary (75 µ internal diameter; 50.5 cm effective length) and an ultraviolet detector set at 360 nm. The optimal background electrolyte was 20 mM sodium tetraborate and 20 mM sodium dodecyl sulfate at pH 9.0 with 3 s hydrodynamic injection at 30 mbar. Electrophoretic analysis took approximately 6.5 min. The correlation coefficient of the calibration curve was 0.999 over the concentration range 2.0–100.0 mg L−1, and the LOD and LOQ values were 0.57 and 1.89 µg mL−1, respectively. The recoveries were from 83.7% to 97.2% with steam distillation as the sample pretreatment method.
Authors:N. Talaie, H. Aghabozorg, and S. Alamdar Milani
In this research, for the first time Nb and Ge were doped into titanosilicate nanoparticles up to 25% simultaneously. Crystalline
phases and morphology of the synthesized samples were studied by X-ray diffraction (XRD) method and scanning electron microscope
(SEM), respectively. Elemental analysis of the samples was performed using X-ray fluorescence (XRF) and Energy dispersive
X-ray (EDX) techniques. Surface area of the samples was measured by BET method. Ion exchange potential of the synthesized
samples for Sr2+ and Cs+ and effective parameters such as concentration, temperature, time, and pH were investigated. In addition,137Cs and 90Sr radio nuclides absorption in the best appropriate sample was examined. The selectivity of the samples for absorption of
137Cs and 90Sr was studied by gamma spectroscopy, liquid scintillation spectrometry, and atomic absorption spectroscopy methods. The obtained
results showed that the prepared samples had good potential for absorption of 137Cs and 90Sr from the model solution. The sample containing equal amount of niobium and germanium, removed completely the 137Cs within the waste water of Tehran nuclear reactor and 90Sr in the desired solution.
Authors:A. Goel, R. Goel, G. Jain Jain, R. Singh Singh, F. Ahmad Ahmad, and G. Singh Singh
A new, specific, sensitive, selective, precise, and reproducible high-performance thin-layer chromatographic (HPTLC) method has been established for study of the stability of 3-acetyl-11-keto-β-boswellic acid (AKBA). HPTLC was performed on aluminium foil plates coated with 200 μm silica gel 60F254. Linear ascending development with toluene-ethyl acetate 7:3 (v/v) was performed at room temperature (25 ± 2°C) in a twin-trough glass chamber saturated with mobile phase vapour. Compact bands (RF 0.52 ± 0.02) were obtained for AKBA. Spectrodensitometric scanning was performed in absorbance mode at 250 nm. Linear regression analysis of the calibration plots showed there was a good linear relationship (r2 = 0.9989 ± 0.0002) between peak area and concentration in the range 200–1200 ng band−1. The method was validated for precision, recovery, robustness, specificity, and detection and quantification limits, in accordance with ICH guidelines. The limits of detection and quantification were 3.06 and 9.29 ng band−1, respectively. The recovery of the method was 99.35–100.21%. AKBA was subjected to various stress test conditions — acid and alkali hydrolysis, oxidation, photodegradation, and dry and wet heat treatment. Degradation products were well resolved from the pure drug with significantly different RF values. Statistical analysis showed the method could be successfully applied for the estimation of AKBA in herbal extract and in nanoparticles. Because the method could effectively separate the drug from its degradation products, it can be regarded as stability-indicating.