Scientific Reports
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2017
·Vol. 7
·期 1
·1-8
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IF 4.259
Zhang Xiaoping,Chingin Konstantin,Zhong Dacai,Liang Juchao,Ouyang Yongzhong,Chen Huanwen
1-Pyrroline has a highly characteristic odor, which is employed by living organisms for chemical signaling and other purposes, but the mechanism whereby this odor is formed remains poorly understood. Here we used a combination of ambient mass spectrometry (AMS) and nuclear magnetic resonance (NMR) spectroscopy to experimentally address the mechanistic aspects of 1-pyrroline volatility and other controversies regarding the chemistry of this compound. Our results indicate that in solution the volatility of the monomer species is significantly higher than that of the trimer species, and 1-pyrroline is evaporated mainly in its monomer state. Neat 1-pyrroline is essentially the pure trimer and displays ca. 100-fold lower evaporation rate than the monomer state in solution. In the gas-phase the trimer species is irreversibly decomposed into monomer species. Under equilibrium conditions the vapor of 1-pyrroline entirely consists of monomer species. The evaporation rate of 1-pyrroline in water has a step-wise dependence on the solution pH, the abrupt increase in volatility (>1,000-fold) occurring around the pKa value of 1-pyrroline (6.8). The pronounced step-wise dependence of 1-pyrroline volatility around neutral pH may also be an important evolutionary factor allowing living systems to regulate the odor strength from very weak to very strong with minimal efforts.
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TOPICS IN CATALYSIS
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2017
·Vol. 60
·期 12
·980-986
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IF 2.486
Zhang Xiuling,Li Zhuang,Zhan Zhibin,Di Lanbo
F-Doped TiO 2 was successfully fabricated using gas–liquid cold plasma with different fluorine sources, including NaF, NaF combined with [C 4 MIM]HSO 4 , and [C 4 MIM]BF 4 . The samples were characterized by XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), and BET (N 2 adsorption–desorption isotherms). Photocatalytic activity of the samples was tested by degradation of methylene blue (MB) dye under simulated sunlight. The results show that doping with different fluorine sources was beneficial to form interstitial F-doped TiO 2 , and ionic liquids used in our work were most favorable to the formation of interstitial F-doped TiO 2 . Calcination of the 0.6-F–[C 4 MIM]BF 4 –TiO 2 sample at 500 °C shows that interstitial F-doped TiO 2 has an excellent thermal stability, a suitable mesoporous structure, higher specific surface area (60.5 m 2 g −1 ) and the best photocatalytic activity. MB degradation was about 98% under the stimulated sunlight for 30 min, and its apparent rate constant was 42 times higher than photolysis and was about 2.9 times as that prepared without addition of ionic liquid. Furthermore, the stability of ionic liquids in the gas–liquid plasma was also investigated and discussed with the assistance of Fourier transform infrared (FTIR) spectroscopy.
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POLYMER TESTING
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2017
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IF 2.464
Wei-Qi Xie,Xin-Sheng Chai
This work reports on a new method for the determination of epoxy groups in epoxy resins by reaction-based headspace gas chromatography (HS-GC). After epoxy resins reacted with hydrochloric acid (HCl) solution, the remaining HCl reacted with bicarbonate solution in a closed headspace vial to form carbon dioxide that was measured by HS-GC. It was found that the first reaction can be finished in 30 min at room temperature and the second reaction, together with headspace equilibration, can be achieved within 15 min at 60 °C. The results showed that the method has a good precision and accuracy, in which the relative standard deviation in the repeatability measurement was 4.20%, and the relative differences between the data obtained by the HS-GC method and the reference method were within 8.04%. The present method is simple, efficient, and suitable for the used in the epoxy resin related research and applications.
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JOURNAL OF CHROMATOGRAPHY A
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2017
·
IF 3.981
Qiaochu Zhang,Meiling Qi,Jinliang Wang
This work reports oligothiophene-functionalized truxene-based stationary phases (TTT, TDT and TFT) with a unique star-shaped π-conjugated architecture for gas chromatographic (GC) separations. They exhibited medium polarity and column efficiency of 3340–3760 plates/m determined by naphthalene at 120 °C. Among them, the TTT stationary phase displayed advantageous resolving capability over the TDT and TFT phases for a wide ranging analytes from apolar to polar, particularly for structural and positional isomers, including alcohols, phenols, halogenated and alkylated benzenes and naphthalenes. Moreover, the TTT column exhibited good thermal stability and repeatability with relative standard deviation (RSD) values of 0.02%–0.07% for run-to-run, 0.10%–0.53% for day-to-day and 2.1%–2.9% for column-to-column, respectively. In addition, it was applied for the determination of isomer impurities in real samples, proving its good potential for practical GC analysis.
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ANALYST
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2014
·Vol. 140
·期 4
·1174-1181
·
IF 3.906
Wei Liu,Renliang Huang,Wei Qi,Mengfan Wang,Rongxin Su,Zhimin He
A novel signal amplification strategy for quartz crystal microbalance (QCM) based on catalytic gas generation was developed to construct an ultrasensitive immunosensor for the detection of proteins (immunoglobulin G, IgG, used as a model). A catalase modified immunoparticle was prepared to form a sandwich-type immunocomplex with the IgG and anti-IgG antibodies that were immobilized on the QCM sensor. The amount of immunoparticles on the sensor surface was thus controlled by the IgG concentration. Then H2O2 was added and catalyzed by catalase for oxygen generation. The generated oxygen replaced some of the liquid on the sensor surface, leading to the change in the shear modulus of the immunocomplex layer and the apparent viscosity and density of the liquid layer. Due to the ultrasensitive response of QCM to these changes, a significant frequency shift related to the IgG concentration was achieved. Different parameters, including the flow cell structure, operation temperature, immunoparticle concentration, and H2O2 concentration were optimized to achieve steady and efficient frequency shifts. Under the optimal conditions, the proposed gas-phase amplified QCM sensor could achieve up to 72 times improvement of detection sensitivity compared to the label-free sensor as a control, in the concentration range of 0.1–3.0 μg mL−1. The detection limit was also reduced from 236 ng mL−1 to 51.0 ng mL−1 at the 3Sblank level.
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Journal of the Taiwan Institute of Chemical Engineers
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2015
·
IF 3
Shidong Tian,Yucui Hou,Weize Wu,Shuhang Ren,Chenxing Wang,Jianguo Qian
The capture of SO 2 by recyclable absorbents has drawn much attention all over the world. In this work, it was found that aqueous calcium lactate (CaL 2 ) solution can be used as a recyclable absorbent for the capture of SO 2 . The solution shows high SO 2 absorption capacities up to 24.8 g SO 2 /kg absorbent at 40 °C. The effects of temperature, excessive lactic acid and CaL 2 concentration on the absorption of SO 2 , the desorption of SO 2 , and the reuse of aqueous CaL 2 solution were systemically studied. Furthermore, the difference between CaL 2 method and traditional calcium method was discussed. Compared with traditional calcium method, there are some advantages, such as regeneration of absorbent, recovery of SO 2 and reduction of CaSO 4 . This work suggests that aqueous CaL 2 solution, which can be obtained at quite low cost, is a promising recyclable absorbent in the process of desulfurization of flue gas.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2015
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IF 2.729
Meiling Zhang,Congcong Wen,Yuan Zhang,Fa Sun,Shuanghu Wang,Jianshe Ma,Kezhi Lin,Xianqin Wang,Guanyang Lin,Lufeng Hu
This study aims to evaluate the effect of ketamine on rats by examining the differences in serum metabolites between ketamine abuse group (Ket-group) and control group (Con-group). Compared to the Con-group, the level of phosphate, propanoic acid, ribitol and d -fructose of the Ket-group increased after continuous intraperitoneal administration of ketamine for 7 days, while the level of alanine, glycine, butanoic acid, valine, l -serine, l -proline, mannonic acid, octadecanoic acid and cholesterol decreased. After 14 days’ administration, the level of alanine, butanoic acid, valine, l -leucine, phosphate, l -serine, l -threonine, propanetricarboxylic acid, hexadecanoic acid and oleic acid of the ketamine group increased while the level of mannonic acid, octadecanoic acid and cholesterol decreased. After stopping ketamine administration for 2 days, the level of butanoic acid, phosphate, aminomalonic acid, gluconic acid, hexadecanoic acid, oleic acid and arachidonic acid of Ket-group increased, while the level of glycine, l -lysine and cholesterol decreased. This study can provide invaluable information for the metabolites changes due to ketamine abuse.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2014
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IF 5.481
Yi Zhao,Yanmei Shen,Guoyi Ma,Rongjie Hao
CO2 separation by molecularly imprinted adsorbent from coal-fired flue gas after desulfurization system has been studied. The adsorbent was synthesized by molecular imprinted technique, using ethanedioic acid, acrylamide, and ethylene glycol dimethacrylate as the template, functional monomer, and cross-linker, respectively. According to the conditions of coal-fired flue gas, the influencing factors, including adsorption temperature, desorption temperature, gas flow rate, and concentrations of CO2, H2O, O2, SO2, and NO, were studied by fixed bed breakthrough experiments. The experimental conditions were optimized to gain the best adsorption performance and reduce unnecessary energy consumption in future practical use. The optimized adsorption temperature, desorption temperature, concentrations of CO2, and gas flow rate are 60 °C, 80 °C, 13%, and 170 mL/min, respectively, which correspond to conditions of practical flue gases to the most extent. The CO2 adsorption performance was nearly unaffected by H2O, O2, and NO in the flue gas, and was promoted by SO2 within the emission limit stipulated in the Chinese emission standards of air pollutants for a thermal power plant. The maximum CO2 adsorption capacity, 0.57 mmol/g, was obtained under the optimized experimental conditions, and the SO2 concentration was 150 mg/m3. The influence mechanisms of H2O, O2, SO2, and NO on CO2 adsorption capacity were investigated by infrared spectroscopic analysis.
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MATERIALS RESEARCH BULLETIN
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2014
·
IF 1.968
Hongwei Che,Aifeng Liu,Junxian Hou,Xiaoliang Zhang,Yongmei Bai,Jingbo Mu,Renliang Wang
In this paper, one-dimensional porous Co 3 O 4 nanobelts were synthesized via a facile template-free hydrothermal method and subsequent the thermal decomposition. Their microstructures and morphologies were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and N 2 adsorption–desorption techniques. The results indicate that the reaction parameters such as the molar ratio of Co(NO 3 ) 2 ·6H 2 O to C 2 H 4 N 4 , the amount of Co(NO 3 ) 2 ·6H 2 O, the hydrothermal temperature and time play crucial rules in controlling the microstructures and morphologies of the as-prepared cobalt precursors. A possible formation mechanism was proposed. Moreover, the obtained porous Co 3 O 4 nanobelts exhibit ethanol gas sensing properties superior to the commercial Co 3 O 4 powders at a working temperature of 200 °C, suggesting their potential applications as nanosensors.
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SENSORS AND ACTUATORS B-CHEMICAL
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2015
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IF 4.097
Yang Li,Huitao Ban,Mujie Yang
Nanocomposites of SnO 2 nanosheets and polypyrrole (PPy) were facilely prepared and their gas sensing properties towards low concentration of NH 3 have been investigated at room temperature. Vertically aligned SnO 2 nanosheets were in situ grown on the substrates via hydrothermal treatment of electrospun nanofibers containing SnCl 2 precursors at a low temperature (135 °C), and coated with PPy by vapor phase polymerization of pyrrole. The SnO 2 nanosheets and the nanocomposites were characterized by X-ray diffraction patterns, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and high resolution transmission microscopy. The nanocomposite sensors exhibited much higher response magnitude towards NH 3 than the sensors based on PPy alone. The effect of the type of doping acids and polymerization time of pyrrole on the sensing properties of the nanocomposites was examined. The nanocomposite sensors revealed sensitive (sensitivity of ∼6.2%/ppm in the range of 1–10.7 ppm of NH 3 , detection limit of ∼257 ppb), selective and repeatable response to NH 3 , and the sensing mechanism has been explored. This work could provide references for the facile preparation of advanced gas sensors based on in situ grown nanostructured metal-oxide semiconductors and their composites.
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ACS Applied Materials & Interfaces
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2014
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IF 5.9
Er-Xia Chen,Hong-Ru Fu,Rui Lin,Yan-Xi Tan,Jian Zhang
A cobalt imidazolate (im) framework material [Co(im)2]n was employed to use as a trimethylamine (TMA) gas sensor and the [Co(im)2]n sensor can be easily fabricated by using Ag–Pd interdigitated electrodes. Gas sensing measurement indicated that the [Co(im)2]n sensor shows excellent selectivity, high gas response and a low detection limit level of 2 ppm to TMA at 75 °C. The good selectivity and high response to TMA of the sensor based on [Co(im)2]n may be attributed to the weak interaction between the TMA molecules and the [Co(im)2]n framework. That may provide an ideal candidate for detecting freshness of fish and seafood.
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SENSORS AND ACTUATORS B-CHEMICAL
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2017
·
IF 5.401
Yao Yao,Mingli Yin,Junqing Yan,Dong Yang,Shengzhong (Frank) Liu
Ag-WO 3 core-shell nanospheres (CSNSs) are fabricated for gas sensor applications. It is found that the sensor based on Ag-WO 3 CSNSs dramatically improve the sensor performance towards alcohol vapor, with significantly lower optimum working temperature (260 °C) and superior detection limit (0.20 ppm) comparing to pure WO 3 hollow nanospheres (HNSs). The Ag-WO 3 sensor displays an ultrahigh sensitivity under visible light illumination. When illuminated under a 150 W xenon arc light source, the response is increased from 62 to 160, the optimum working temperature is reduced from 260 to 190 °C, and the detection limit is improved from 0.20 to 0.032 ppm. This work may offer an attractive strategy to improve sensitivity of light-enhanced plasmonic metal-oxide based gas sensors.
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