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acid base strong ion

Daniel Martín-Yerga, Alejandro Pérez-Junquera, María Begoña Gonzalez-Garcia, David Hernández-Santos, Pablo Fanjul-Bolado
Spectroelectrochemical techniques are becoming increasingly versatile tools to solve a diverse range of analytical problems. Herein, the use of in situ real-time luminescence spectroelectrochemistry to quantify chloride ions is demonstrated. Utilizing the bleaching effect of chlorine-based electrogenerated products after chloride oxidation, it is shown that the fluorescence of the Rhodamine 6G dye decrease proportionally to the initial chloride concentration in solution. A strong decrease of fluorescence is observed in acidic media compared to a lower decrease in alkaline media, which suggests that Cl2 , favourably generated at low pH, could be the main species responsible of the fluorescence loss...
May 18, 2018: Analytical Chemistry
Mohammed Jaoui, Michael Lewandowski, John H Offenberg, Maribel Colon, Kenneth S Docherty, Tadeusz E Kleindienst
The analytical capabilities associated with the use of silylation reactions have been extended to a new class of organic molecules, nitroaromatic compounds (NACs). These compounds are a possible contributor to urban particulate matter of secondary origin which would make them important analytes due to their (1) detrimental health effects, (2) potential to affect aerosol optical properties, (3) and usefulness for identifying PM2.5 from biomass burning. The technique is based on derivatization of the parent NACs using N,O-bis-(trimethylsilyl)-trifluoro acetamide, one of the most prevalent derivatization reagent for analyzing hydroxylated molecules, followed by GC-MS using electron ionization (EI) and methane chemical ionization (CI)...
May 15, 2018: Journal of Mass Spectrometry: JMS
Amir Taghavi Nasrabadi, Lev David Gelb
Protic ionic liquids (PILs) form through proton transfer from a Brönsted acid to a Brönsted base. In this work we use molecular dynamics simulation to study how PIL properties vary with χ, the extent of the proton transfer reaction. Three PILs are considered: N-propylammonium acetate, [N3][Ac], N-butylammonium acetate, [N4][Ac], and N, N-dimethylbutylammonium acetate, [N114][Ac]. In all cases density and viscosity increase with increasing χ, while diffusivities of all species decrease with increasing χ...
May 11, 2018: Journal of Physical Chemistry. B
Fengyang Wang, Yingying Zhu, Jie Xu, Zhiai Xu, Guiying Cheng, Wen Zhang
Cysteine (Cys) is a bithiol that plays a vital role in many physiological processes. However, it is difficult to discriminate Cys from homocysteine (Hcy) and glutathione (GSH), due to their similar chemical structures and reactivity. Herein, we have developed a polymeric nanoprobe, nanoHFA, for ratiometric, highly selective, and sensitive detection of Cys based on 7-hydroxycoumarin-3-carboxylic acid (HC) and fluorescein isothiocyanate (FITC)-acrylate (FITC-A) group-functionalized lipopolymer DSPE-PEG. The probe nanoHFA showed a strong fluorescence emission peak centered at 450 nm attributed to HC and a weak fluorescence emission peak centered at 520 nm due to the photoinduced electron transfer (PET) process of FITC induced by acrylate group...
May 11, 2018: Analytical and Bioanalytical Chemistry
Cong Kong, Yang Wang, Yuanfei Huang, Huijuan Yu
A quick screening method of more than 200 pharmaceutical and other residues in aquatic foods based on ultrahigh-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (UHPLC-Q/Orbitrap MS) was established. In this method, after the addition of 200 μL of 1 M EDTA-Na2 , 2 g of each sample homogenate was extracted successively with 10 mL of acetonitrile and 10 mL of ethyl acetate. The extracts were combined, dried under nitrogen flow, and redissolved in 0.1% formic acid in acetonitrile/water (4:6, v/v) for analysis...
May 11, 2018: Analytical and Bioanalytical Chemistry
Jiayan Du, Mengxin Zhao, Wei Huang, Yuequan Deng, Yi He
We report a molybdenum oxide (MoO3 ) nanomaterial-based three-input logic gate that uses Sn2+ , NO2 - , and H+ ions as inputs. Under acidic conditions, Sn2+ is able to reduce MoO3 nanosheets, generating oxygen-vacancy-rich MoO3-x nanomaterials along with strong localized surface plasmon resonance (LSPR) and an intense blue solution as the output signal. When NO2 - is introduced, the redox reaction between the MoO3 nanosheets and Sn2+ is strongly inhibited because the NO2 - consumes both H+ and Sn2+ . The three-input logic gate was employed for the visual colorimetric detection of Sn2+ and NO2 - under different input states...
May 9, 2018: Analytical and Bioanalytical Chemistry
Tao He, Yong-Zheng Zhang, Xiang-Jing Kong, Jiamei Yu, Xiu-Liang Lv, Yufeng Wu, Zhen-Ji Guo, Jian-Rong Li
Dichromate is known for severe health impairments to organisms. New and valid strategies have been developed to rapidly detect and efficiently remove this pollutant. Constructing stable luminescent metal-organic frameworks (MOFs) for dichromate recognition and removal from aqueous solution could provide a feasible resolution to this problem. Herein, a new luminescent Zr(IV)-MOF, Zr6 O4 (OH)7 (H2 O)3 (BTBA)3 (BUT-39, BUT = Beijing University of Technology) was constructed through the reaction of a newly designed functionalized T-shaped ligand 4,4',4″-(1 H-benzo[ d]imidazole-2,4,7-triyl)tribenzoic acid (H3 BTBA) with zirconium salt...
May 7, 2018: ACS Applied Materials & Interfaces
Zhengfei Wang, Yuze Bai, Daizhen Zhang, Boping Tang
Osmoregulation is an important mechanism by which euryhaline crustaceans regulate osmotic and ionic concentrations. The Chinese mitten crab (Eriocheir sinensis) is a strong osmoregulating animal model among crustacean species, as it can maintain its hemolymph composition and survives well in either seawater or freshwater. Osmoregulation by E. sinensis during physiological adaptation has been studied extensively. However, the genetic basis of osmoregulation in E. sinensis for acclimating to changing salinities remains unclear...
May 4, 2018: Genetica
Michalis Agrafiotis, Dimitrios Mpliamplias, Maria Papathanassiou, Fotini Ampatzidou, Georgios Drossos
PURPOSE: To suggest a simplified method for strong ion gap ([SIG]) calculation. PATIENTS AND METHODS: To simplify [SIG] calculation, we used the following assumptions: (1) the major determinants of apparent strong ion difference ([SIDa ]) are [Na+ ], [K+ ] and [Cl- ] (2) [Ca2+ ] and [Mg2+ ] do not contribute significantly to [SIDa ] variation and can be replaced by their reference concentrations (3) physiologically relevant pH variation is at the order of 10-2 and therefore we can assume a standard value of 7...
May 3, 2018: Journal of Anesthesia
Angelos-Gerasimos Ioannidis, Frederiek-Maarten Kerckhof, Yasmine Riahi Drif, Mike Vanderroost, Nico Boon, Peter Ragaert, Bruno De Meulenaer, Frank Devlieghere
Fresh cut iceberg lettuce spoilage was studied considering the microbial and biochemical activity, the formation of volatile organic compounds (VOC) and consumer acceptability. Lettuce was packaged under three different packaging conditions and stored at 4 °C for 10 days: anaerobic packaging (ANAER), equilibrium modified atmosphere packaging with 3% O2 (EMAP) and perforated packages (AIR). Results indicated a clear distinction between packaging conditions. EMAP and AIR resulted in a short shelf life (≤5...
April 22, 2018: International Journal of Food Microbiology
Lingdong Kong, Chengtian Du, Assiya Zhanzakova, Tiantao Cheng, Xin Yang, Lin Wang, Hongbo Fu, Jianmin Chen, Shicheng Zhang
Heterogeneous aqueous reaction plays important roles in the enhanced formation of secondary aerosols during haze. However, its occurrence in haze episodes remains poorly understood. In this study, the trends in heterogeneous aqueous reaction in continuous haze episodes were investigated by an in-depth case analysis. The highly time-resolved measurements of water-soluble inorganic ions of PM2.5 were conducted in a suburban of Shanghai, China, and continuous haze episodes, which occurred from Feb. 18 to Feb. 28, were selected as studied cases...
April 13, 2018: Science of the Total Environment
Li Zhao, Huiyu Li, Yuan Xu, Haochi Liu, Tianyu Zhou, Ning Huang, Yi Li, Lan Ding
Highly selective nitrogen-doped carbon quantum dots (ND-CQDs) for copper ion (Cu2+ ) determination were synthesized by a solvent-free pyrolysis of citric acid and histidine. The resultant ND-CQDs display a stable bright blue fluorescence with a satisfactory product yield of 56% and quantum yield of 16%. The ND-CQDs not only show good photostability under continuous UV irradiation, but are also dramatically stable against extreme ionic strengths. The solid powders of the ND-CQDs re-dispersed in water still maintain a strong blue fluorescence after storing at room temperature for 6 months...
April 30, 2018: Analytical and Bioanalytical Chemistry
Genki Saito, Hitoshi Sasaki, Heishichiro Takahashi, Norihito Sakaguchi
Silicon anodes have attracted considerable attention for their use in lithium-ion batteries because of their extremely high theoretical capacity; however, they are prone to extensive volume expansion during lithiation, which causes disintegration and poor cycling stability. In this article, we use two approaches to address this issue, by reducing the size of the Si particles to nanoscale and incorporating them into a carbon composite to help modulate the volume expansion problems. We improve our previous work on the solution-plasma-mediated synthesis of Si nanoparticles (NPs) by adjusting the electrolyte medium to mild buffer solutions rather than strong acids, successfully generating Si-NPs with <10 nm diameters...
April 27, 2018: Nanomaterials
Delong Kong, Ning Qiao, Nian Wang, Zhuo Wang, Qi Wang, Zhiyong Zhou, Zhongqi Ren
A novel nanostructured magnetic ion-imprinted polymer (IIP) was synthesized for the selective adsorption of Pb(ii) from aqueous solution. The IIP was prepared on functional Fe3O4@SiO2 core/shell nanoparticles as a support. Monomer units in the polymer featured the typical bidentate ligand itaconic acid. We used ethylene glycol dimethacrylate and 2,2-azoisobisbutyronitrile as a cross-linker and an initiator, respectively. Monomers with different acid-base properties and different proportions of cross-linker were investigated to obtain high-performance adsorbents...
May 9, 2018: Physical Chemistry Chemical Physics: PCCP
Hyun Jeong Kwak, Oh Kyung Lim, Jae Myung Baik, Youn Yi Jo
Background: To compare the effects of intraoperative infusions of balanced electrolyte solution (BES)-based hydroxyethyl starch (HES) and saline-based albumin on metabolic acidosis and acid/base changes during major abdominal surgery conducted using Stewart's approach. Methods: Forty patients, aged 20-65 years, undergoing major abdominal surgery, were randomly assigned to the HES group (n = 20; received 500 ml of BES-based 6% HES 130/0.4) or the albumin group (n = 20; received 500 ml of normal saline-based 5% albumin)...
April 24, 2018: Korean Journal of Anesthesiology
Denglang Zou, Yurong Du, Jianyuan Kuang, Shihao Sun, Jianbin Ma, Renwang Jiang
This study presents an efficient strategy based on pH-zone-refining counter-current chromatography with a hydrophilic organic/salt-containing two-phase system composed of acetonitrile, sodium chloride and water for preparative separation of polar alkaloids from natural products. Acetonitrile-sodium chloride-water system provides a wider range of polarity for polar alkaloids than classical aqueous two-phase systems. It gets rid of the effect of free hydrogen ion, strong ionic strength, hold low viscosity and the sharp retainer border could be formed easily...
April 10, 2018: Journal of Chromatography. A
Roswitha Siener
Chronic kidney disease and reduced glomerular filtration rate are risk factors for the development of chronic metabolic acidosis. The prevention or correction of chronic metabolic acidosis has been found to slow progression of chronic kidney disease. Dietary composition can strongly affect acid⁻base balance. Major determinants of net endogenous acid production are the generation of large amounts of hydrogen ions, mostly by animal-derived protein, which is counterbalanced by the metabolism of base-producing foods like fruits and vegetables...
April 20, 2018: Nutrients
Mengfan Zhai, Feng Ma, Junying Li, Binbin Wan, Ning Yu
A novel supermacroporous poly(hydroxypropyl methacrylate) (p(HPMA)) cryogel was synthesized by cryogelation method at -16 °C. In this synthesis process, HPMA was used as a monomer, and N,N'-methylenebisacrylamide (MBAAm) was used as cross-linker; the reaction was carried out in the presence of redox initiator pair N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS). The effect of monomer concentration, cross-linker content, cooling rate, and dioxane co-solvent were determined with respect to the pore structure, mechanical behavior, swelling degree, and porosity of cryogel...
April 18, 2018: Journal of Biomaterials Science. Polymer Edition
Prasanna Neelakantan, Todd Berger, Carolyn Primus, Hagay Shemesh, Paul R Wesselink
Bioactive hydraulic tricalcium silicate materials are commonly used in several dental procedures. Mineral Trioxide Aggregate (MTA) is one such material, which is used in a variety of clinical applications, the most recent of which is root canal sealing material, during which, the MTA potentially comes in contact with remnants of the chemical agents used for disinfecting root canals. The effects of commonly used root canal irrigating solutions on MTA have not been investigated in depth, thus far. The aim of this study was to determine the effect of five common chemical agents used in root canal preparation (sodium hypochlorite/NaOCl, ethylene diaminetetraacetic acid/EDTA, mixture of sodium hypochlorite and etidronic acid/NaOCl + EA, mixture of EDTA and Chlorhexidine/QMix, or saline) on a commercial tricalcium silicate (MTA Plus)...
April 15, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Yerin Kang, Woonwoo Lee, Geupil Jang, Bong-Gyu Kim, Youngdae Yoon
Despite the large number of bioreporters developed to date, the ability to detect heavy metal(loid)s with bioreporters has thus far been limited owing to the lack of appropriate genetic systems. We here present a novel approach to modulate the selectivity and sensitivity of microbial whole-cell bioreporters (WCBs) for sensing metal(loid)s via the znt-operon from Escherichia coli, which were applied to quantify the bioavailability of these contaminants in environmental samples. The WCB harboring the fusion gene zntAp::egfp was used as a microbial metal(loid) sensor, which was turned on by the interaction between ZntR and metal(loid) ions...
April 7, 2018: Applied Microbiology and Biotechnology
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