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Solution liquid solid

I Reinholds, I Pugajeva, Dz Zacs, E Lundanes, J Rusko, I Perkons, V Bartkevics
A solid-phase extraction (SPE) method based on multi-walled carbon nanotubes (CNT) was developed for the determination of 12 acidic non-steroidal anti-inflammatory drugs (NSAIDs) in surface waters and tap water. Pristine and functionalised CNTs were evaluated as sorbent materials. Batch experiments were used to optimise sorption and desorption conditions (sorbent type and amount, adsorption time, pH). The adsorption equilibrium was reached after 8 to 48 h duration, which increased with the pH of solution. Non-agglomerated pristine CNTs (20 mg) showed the most optimal adsorption (94 to 100%) for all of the analytes after a 30-min contact period in acidified water solutions (100 mL)...
October 18, 2017: Environmental Monitoring and Assessment
Christian Celia, Angela Scala, Rosanna Stancanelli, Emanuela Surdo, Donatella Paolino, Alessandro Grattoni, Nicola Micale, Vincenza Crupi, Domenico Majolino, Massimo Fresta, Silvana Tommasini, Valentina Venuti, Cinzia Anna Ventura
Hydroxypropyl-β-cyclodextrin (HP-β-CyD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CyD) were used to generate hydrophilic complexes of the poorly water-soluble drug testosterone propionate (TP). The inclusion complexes were obtained by freeze-drying, and then analyzed at both liquid and solid states. Phase solubility studies, performed according to the type-AL solubility diagrams of TP in presence of both CyDs, suggested the formation of water-soluble complexes at 1:1 molar ratio. These results were confirmed by continuous variation method (Job's plot)...
October 14, 2017: International Journal of Pharmaceutics
Claudia Oellig, Jessica Radovanovic
16-O-Methylcafestol (16-OMC), the characteristic diterpene exclusively present in Coffea canephora, is an excellent marker for Coffea canephora admixtures to Coffea arabica. Here we show a straightforward, selective and sensitive screening method for the determination of 16-OMC in roasted coffee by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD). As internal standard, Sudan IV was used, and a direct saponification with 10% ethanolic potassium hydroxide solution was followed by solid supported liquid extraction with petroleum ether...
October 12, 2017: Journal of Chromatography. A
M Sherif El-Eskandarany, Ehab Shaban, Fahad Aldakheel, Abdullah Alkandary, Montaha Behbehani, M Al-Saidi
Storing hydrogen gas into cylinders under high pressure of 350 bar is not safe and still needs many intensive studies dedic ated for tank's manufacturing. Liquid hydrogen faces also severe practical difficulties due to its very low density, leading to larger fuel tanks three times larger than traditional gasoline tank. Moreover, converting hydrogen gas into liquid phase is not an economic process since it consumes high energy needed to cool down the gas temperature to -252.8 °C. One practical solution is storing hydrogen gas in metal lattice such as Mg powder and its nanocomposites in the form of MgH2...
October 16, 2017: Scientific Reports
Hongming Lou, Meijun Zeng, Qiaoyan Hu, Cheng Cai, Xuliang Lin, Xueqing Qiu, Dongjie Yang, Yuxia Pang
Effects of nonionic surfactants on enzymatic hydrolysis of Avicel at different agitation rates and solid loadings and the mechanism were studied. Nonionic surfactants couldn't improve the enzymatic hydrolysis efficiency at 0 and 100rpm but could enhance the enzymatic hydrolysis significantly at high agitation rate (200 and 250rpm). Cellulase was easily deactivated at high agitation rate and the addition of nonionic surfactants can protect against the shear-induced deactivation, especially when the cellulase concentration was low...
July 14, 2017: Bioresource Technology
Grace M Nisola, Kris Niño G Valdehuesa, Alex V Anonas, Kristine Rose M Ramos, Won-Keun Lee, Wook-Jin Chung
The feasibility of open-pore polyurethane (PU) foam as packing material for wet chemical scrubber was tested for NH3 and H2S removals. The foam is inexpensive, light-weight, highly porous (low pressure drop) and provides large surface area per unit volume, which are desirable properties for enhanced gas/liquid mass transfer. Conventional HCl/HOCl (for NH3) and NaOH/NaOCl (for H2S) scrubbing solutions were used to absorb and oxidize the gases. Assessment of the wet chemical scrubbers reveals that pH and ORP levels are important to maintain the gas removal efficiencies >95%...
October 16, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Nannan Guo, Baohong Hou, Na Wang, Yan Xiao, Jingjing Huang, Yanmei Guo, Shuyi Zong, Hongxun Hao
In this paper, the solution-mediated polymorphic transformation of rifampicin was investigated and simulated in three solvents at 30 °C. The solid state form I and form II of rifampicin was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Raman spectroscopy and fourier transform infrared spectroscopy (FTIR). To explore the relative stability, solubility data of form I and form II of rifampicin in butan-1-ol were determined using a dynamical method...
October 11, 2017: Journal of Pharmaceutical Sciences
Jingyi Zhang, Donghao Liu, Xiaoyan Meng, Yi Shi, Ruya Wang, Deli Xiao, Hua He
In this study, a novel solid phase extraction based on porous magnetic graphene oxide-cyclodextrin polymers (MGO-CD) was developed with aromatic linker and used for the simultaneous extraction and preconcentration of trace antiepileptic drugs in plasma. The characteristics of MGO-CD were assessed by Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller surface areas (BET), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM)...
October 4, 2017: Journal of Chromatography. A
Xinge Cui, Xin Zheng, Ji Jiang, Fenlai Tan, Lieming Ding, Pei Hu
BPI-9016M is a novel dual-target small-molecule inhibitor targeting c-Met and AXL, which was developed by Betta Pharmaceuticals Co., Ltd (Hangzhou, China). It has great potential in the treatment of advanced cancer. A high throughput quantitation method, based on liquid chromatography-tandem mass spectrometry, was developed and validated for the simultaneous determination of BPI-9016M and its main metabolite, M1 and M2-2, in human plasma with a sample preparation method of precipitation of protein. Liquid chromatographic separation was performed with a gradient elution of formic acid-10mM ammonium acetate aqueous solution (1:1000, v/v) and acetonitrile at a flow rate of 0...
October 8, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Chip J Smith, Durgesh Vinod Wagle, Hugh M O'Neill, Barbara R Evans, Sheila N Baker, Gary A Baker
To fully leverage the advantages of ionic liquids for many applications, it is necessary to immobilize or encapsulate the fluids within an inert, robust, quasi-solid-state format that does not disrupt their many desirable, inherent features. The formation of ionogels represents a promising approach, however, many earlier approaches suffer from solvent/matrix incompatibility, optical opacity, embrittlement, matrix-limited thermal stability, and/or inadequate ionic liquid loading. We offer a solution to these limitations by demonstrating a straightforward and effective strategy toward flexible and durable ionogels comprising bacterial cellulose supports hosting as much as 99% ionic liquid by total weight...
October 10, 2017: ACS Applied Materials & Interfaces
Koji Furukawa, Makoto Hashimoto, Satoshi Kaneco
A rapid determination of aniline in environmental water was examined based on liquid chromatography/tandem mass spectrometry (LC/MS/MS). Environmental water samples were diluted 20-fold with Mill-Q water and measured by LC/MS/MS after adding a surrogate substance (aniline-d5). In the results of the present study, the calibration curve of aniline showed good linearity in the range of 0.05 - 2.0 μg/L. Since the RSD (repeatability) by measuring repeatedly an aniline standard solution (0.05 μg/L, n = 7) was 3...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Adrian Rodriguez, Rosa Maria Gomila, Gabriel Martorell, Antonia Costa-Bauza, Felix Grases
Quantitative analysis of relevant metabolites in biofluids such as urine is often a tedious procedure, since it usually requires extraction, purification or preconcentration. For instance, in the analysis of methylxanthines in urine, a solid-phase extraction is often required. In the current work, a rapid and highly sensitive "dilute-and-shoot" method combining ultra-high-performance liquid chromatography and high-resolution mass spectrometry (UHPLC/HRMS) was validated for urinary determination of twelve analytes: uric acid, hypoxanthine, xanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, theophylline, theobromine, paraxanthine and caffeine...
October 2, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Zhongjin He, Praveen Linga, Jianwen Jiang
Microsecond simulations have been performed to investigate CH4 hydrate formation from gas/water two-phase systems between silica and graphite surfaces, respectively. The hydrophilic silica and hydrophobic graphite surfaces exhibit substantially different effects on CH4 hydrate formation. The graphite surface adsorbs CH4 molecules to form a nanobubble with a flat or negative curvature, resulting in a low aqueous CH4 concentration; and hydrate nucleation does not occur during 2.5 s simulation. Moreover, ordered interfacial water bilayer forms between the nanobubble and graphite surface thus preventing their direct contact...
October 9, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Xin Qi, Kristen A Fichthorn
Though many experimental studies have documented that certain solution-phase additives can play a key role in the shape-selective synthesis of metal nanocrystals, the origins and mechanisms of this shape selectivity are still unclear. One possible role of such molecules is to thermodynamically induce the equilibrium shape of a nanocrystal by altering the interfacial free energies of the facets. Using a multi-scheme thermodynamic integration method that we recently developed [J. Chem. Phys., 2016, 145, 194108], we calculate the solid-liquid interfacial free energies γsl and investigate the propensity to achieve equilibrium shapes in such syntheses...
October 9, 2017: Nanoscale
Tao Zhang, Thomas Doert, Michael Ruck
Homogeneous powders of almost spherical particles of SrTiO3 with diameters of about 1 μm and large surface areas of up to 186 m(2) g(-1) were obtained from a facile one-pot solvothermal synthesis. Thorough characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), (high-resolution) transmission electron microscopy, and nitrogen physisorption measurements revealed the hierarchical architecture of the particles down to the scale of a few nanometers. In contrast to SrTiO3 samples obtained by high-temperature solid-state reaction, the particles are neither agglomerated nor sintered above the micrometer scale...
October 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Silvana S S Cardoso, Julyan H E Cartwright
Black smokers and Lost City-type springs are varieties of hydrothermal vents on the ocean floors that emit hot, acidic water and cool, alkaline water, respectively. While both produce precipitation structures as the issuing fluid encounters oceanic water, Lost City-type hydrothermal vents in particular have been implicated in the origin of life on the Earth. We present a parallel-velocity flow model for the radius and flow rate of a cylindrical jet of fluid that forms the template for the growth of a tube precipitated about itself and we compare the solution with previous laboratory experimental results from growth of silicate chemical gardens...
September 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Mohammad Halayqa, Aneta Pobudkowska, Urszula Domańska, Maciej Zawadzki
Synthesis of three mefenamic acid (MEF) derivatives - ionic liquid compounds composed of MEF in an anionic form and ammonium cation (choline, MEF1), or {di(2-hydroxyethyl)dimethyl ammonium (MEF2)}, or {tri(2-hydroxyethyl)methyl ammonium compound (MEF3)} is presented. The basic thermal properties of pure compounds i.e. fusion temperatures, and the enthalpy of fusion of these compounds have been measured with differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method...
October 3, 2017: European Journal of Pharmaceutical Sciences
Geng Nan Wang, Ning Peng Wu, Xin He, Hui Cai Zhang, Jing Liu, Jian Ping Wang
In this study, a magnetic graphene-based dispersive solid phase extraction method was first developed for extraction of β-agonists in urine. During the experiments, the absorbent amount, sample pH, extraction time, elution solution and elution time were optimized respectively. The optimized extraction method was finished within 10min, and showed high enrichment factors for 9 β-agonists (20-26 folds). Furthermore, this absorbent could be reused for at least 60 times. Then this extraction method was combined with ultra performance liquid chromatography triple quadrupole tandem mass spectrometry to determine the 9 drugs in urine...
September 28, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Vivek Dhiman, Dilip Kumar Singh, Mayurbhai Kathadbhai Ladumor, Saranjit Singh
The degradation behavior of amodiaquine dihydrochloride, an antimalarial drug, was investigated in solution as well as solid states. The drug was subjected to hydrolytic, photolytic, oxidative and thermal stress conditions, according to International Conference on Harmonization guideline Q1A(R2). It showed extensive hydrolysis in acidic, alkaline and neutral solutions both with and without light, while it proved to be stable to thermal and oxidative conditions. In total, six degradation products were formed, which were separated on a C8 column, employing a gradient reversed-phase high-performance liquid chromatography method in which acetonitrile and 10 mM ammonium formate (pH 3...
October 6, 2017: Journal of Separation Science
Fajun Zhang
Classical nucleation theory (CNT), which was established about 90 years ago, has been very successful in many research fields, and continues to be the most commonly used theory in describing the nucleation process. For a fluid-to-solid phase transition, CNT states that the solute molecules in a supersaturated solution reversibly form small clusters. Once the cluster size reaches a critical value, it becomes thermodynamically stable and favored for further growth. One of the most important assumptions of CNT is that the nucleation process is described by one reaction coordinate and all order parameters proceed simultaneously...
October 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
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