JOURNAL OF SURFACTANTS AND DETERGENTS
·
2015
·Vol. 18
·期 6
·1081-1088
·
IF 1.685
Binglei Song,Zonghui Xu,Xiaona Yu,Shuyi Chen,Shunan Li,Rongzhen Shi,Zhenggang Cui
Modification of the molecular structure of surfactants is an effective method for exploring their self-assembly. A double-tailed quaternary ammonium surfactant with a protrudent head group, namely 2-octyldecyltrimethylammonium bromide (2-ODTAB) was synthesized, and the solution properties were investigated by surface tension, dynamic light scattering, and cryogenic TEM. A comparative study was also performed on the traditional double-tailed homologue surfactants dioctyldimethylammonium bromide (8–8), didecyldimethylammonium bromide (10–10), and didodecyldimethylammonium bromide (12–12). The results showed that 2-ODTAB was more effective at lowering surface tension and in forming stable vesicles than traditional double-tailed surfactants with similar alkyl chain length. The reason is attributed to the improved structure of 2-ODTAB, in which the two alkyl tails are connected to the ionic head group by one carbon atom. This structure imparts more freedom to the head group and thus favors formation of more stable aggregates at low concentration. In addition, the lower limit of the alkyl chain length of the double-tailed surfactants for forming stable vesicles was illustrated.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2015
·Vol. 122
·期 2
·717-723
·
IF 2.042
Luo Fubin,Wu Kun,Guo Huilong,Zhao Qiang,Liang Liyan,Lu Mangeng
Cellulose whisker (CW) is employed as a novel carbonization agent to build green and efficient intumescent flame retardant (CWAPP) with ammonium polyphosphate (APP). Due to the presence of CW, CWAPP exhibits more excellent flame retardancy compared with APP in rigid polyurethane foam (PU). PU-added CWAPP (PU/CWAPP) obtains higher LOI value than that with the same loading of APP. Results also indicate that CWAPP have better water resistance compared with APP in PU. Flame-retardant property of PU/APP is decreased remarkably after soaked in hot water. By comparison, that of PU/CWAPP is rarely changed after the same treatment. CWAPP also shows a positive effect on the mechanical property in PU, and compression strength of PU/CWAPP is higher than that of PU/APP with the same content of flame retardant.
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JOURNAL OF POROUS MATERIALS
·
2015
·Vol. 22
·期 2
·465-471
·
IF 1.108
Liu Shu-Cheng,Yue Zi-Feng,Liu Yi
Mesoporous carbon–ZrO 2 (MCZ) composites are prepared using a simple thermal conversion of metal–organic frameworks (MOFs). By choosing a zirconium based MOFs, called UiO-66, as both the Zr and C precursor and the porous template, porous carbon–ZrO 2 hybrid materials are formed by carbonizing UiO-66 at 600 °C in an inert atmosphere. The structure, morphology, and porosity of the products were studied using powder X-ray diffraction, transmission electron microscopy, thermogravimetry, and the BET surface area method. The obtained MCZ materials exhibit a relatively high specific surface area of ~136 m 2 g −1 , a large pore size, and pore volumes of ~9.6 nm and ~0.33 cm −3 g −1 , respectively. The results also indicate that the MCZ materials have a good capacity to adsorb Congo red from an aqueous solution.
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JOURNAL OF MATERIALS SCIENCE
·
2015
·Vol. 51
·期 2
·893-902
·
IF 2.371
Wang Desong,Xu Zexuan,Luo Qingzhi,Li Xueyan,An Jing,Yin Rong,Bao Cai
An efficient visible-light photocatalyst was successfully synthesized by surface-hybridizing graphitic carbon nitride (g-C 3 N 4 ) using a small amount of cadmium sulfide (CdS) nanoparticles. The CdS/g-C 3 N 4 nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy, and photocurrent–time measurement. The photocatalytic activity of the CdS/g-C 3 N 4 nanocomposites was investigated by evaluating the degradation of Rhodamine B (RhB) under visible-light irradiation. The effects of the CdS content on the nanocomposites, initial RhB concentration, pH value of the investigated system, and dosage of CdS/g-C 3 N 4 nanocomposites on the visible-light photocatalytic activity were systematically investigated. The results revealed that the visible-light photocatalytic activity of g-C 3 N 4 -based photocatalysts was significantly improved by surface-hybridization of a small amount of CdS nanoparticles, increased as both CdS content on the nanocomposites and dosage of CdS/g-C 3 N 4 nanocomposites increased, while increased at first and then decreased as both initial RhB concentration and pH value of the investigated system increased. The visible-light photocatalytic mechanism of the CdS/g-C 3 N 4 nanocomposites was discussed.
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MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 15
·2607-2613
·
IF 3.741
Yang Zhiqing,Xie Liyan,Yin Huanshun,Zhou Yunlei,Ai Shiyun
We describe an electrochemical bioassay for the detection of the activity of methyltransferase (MTase), and for screening this enzyme’s inhibitors. The assay is based on the conjugation of a hemin to a G-quadruplex that enables enzymatic signal amplification with the aid of exonuclease III (ExoIII). In the first step, double-stranded DNA containing the quadruplex-forming oligomer is assembled on the surface of a gold electrode and then methylated by DNA adenine methyltransferase (DAM). After cleaved by endonuclease DpnI, the methylated DNA is digested by ExoIII and the quadruplex-forming oligomers are liberated. This leads to the formation of a hemin/G-quadruplex (in presence of hemin and of potassium ions). The hemin/G-quadruplex catalyzes the oxidization of hydroquinone by H 2 O 2 and the benzoquinone was formed to generate electrochemical signal. Finally, the gold electrode modified with reduced graphene oxide was used as working electrode for performing differential pulse voltammetry. The method has a detection limit of 0.31 unit · mL −1 . A study on the inhibition of MTase showed it was inhibited by epicatechin with an IC50 value of 157 μM.
We describe an electrochemical bioassay for the detection of the activity of methyltransferase and for screening for its inhibitors. Due to the conjugation of a hemin to a G-quadruplex, strong enzymatic signal amplification is enabled with the aid of exonuclease III.
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Science China-Chemistry
·
2015
·Vol. 59
·期 3
·350-359
·
IF 1.695
Yan Han,Du Qing,Yang Hu,Li Aimin,Cheng Rongshi
A magnetic reduced graphene oxide composite (MRGO) was successfully prepared by a simple and green method. MRGO was then used as an adsorbent and found to exhibit enhanced removal efficiency for various chlorophenols (CPs) from water compared with its precursors, graphene oxide (GO) and reduced graphene oxide. The CPs were o -chlorophenol, p -chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Among them, 2,4,6-trichlorophenol, which exhibited the lowest water solubility and highest molecular weight, most easily bound to MRGO. The preferential interactions between MRGO and CPs were hydrophobic interactions (π-π stacking and hydrophobic effect). This result was confirmed by the equilibrium adsorption behavior in which isotherms were all well described by Freudlich model, indicating heterogeneous and multilayer adsorption. Therefore, CP adsorption was more favored under neutral and acidic conditions, and the decreased removal efficiency of MRGO at higher pH levels was due to the improved hydrophilicity of CPs for deprotonation effect. Moreover, MRGO showed fast removal of each CP, achieving adsorption equilibrium within 10.0 min, presented efficient separation from water under an external magnetic field, and was easily regenerated using dilute NaOH aqueous solution after reaching saturated adsorption. Adsorption capacity of the regenerated MRGO had almost no loss until after five cycles. In summary, MRGO was an efficient adsorbent for the removal of various CPs and had considerable application potential in water treatment.
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JOURNAL OF POROUS MATERIALS
·
2015
·Vol. 23
·期 2
·489-495
·
IF 1.108
Pan Yani,Zhang Jingji,Xu Yu,Gao Yafeng,Chen Zhi,Wang Jiangying
Sulfonated mesoporous ZrO 2 was prepared by a facile one-pot hydrothermal process, using a mixture of ZrOCl 2 ·8H 2 O and sodium dodecyl sulfonate in a NaOH solution, and subsequent calcination of the inorganic/organic intermediate. The influence of NaOH concentration, hydrothermal and calcination temperature on the structural and textural properties of the final products was investigated. Increasing the NaOH concentration gave rise to the transformation from tetragonal to monoclinic and then to tetragonal phase, whereas the increase of hydrothermal temperature led to the tetragonal-to-monoclinic phase transformation. As the NaOH concentration and hydrothermal temperature were increased, a narrow pore size distribution was turned into a multi-modal pore size distribution resulting from regular mesopores and interparticle voids. Accordingly, the incorporated sulfonate anions were oxidized into sulphate anions. After the calcination of 550 °C, the sulfonated products possessed tetragonal crystalline phase with average pore diameter of 4.2 nm and surface area of 108 m 2 g −1 .
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Forensic Toxicology
·
2014
·Vol. 32
·期 2
·331-337
·
IF 5.756
Wurita Amin,Hasegawa Koutaro,Minakata Kayoko,Watanabe Kanako,Suzuki Osamu
Traffic police brought five dubious herbal product packages to our laboratory for toxicological analysis. These products usually contain one or multiple kinds of synthetic cannabinoids. In one of the packages, we identified the coexistence of a new type of dubious drug (diphenidine) with the synthetic cannabinoid 5-fluoro-AB-PINACA. Conclusive identification was performed by comparison of the mass spectra of the test herb extracts with those of the reference standards of diphenidine and 5-fluoro-AB-PINACA by both gas chromatography–mass spectrometry (GC–MS) and electrospray ionization–tandem mass spectrometry. Both mass spectra of the test extracts coincided with those of the reference standards for each MS method. Diphenidine and 5-fluoro-AB-PINACA were quantitated in the herbal product by GC–MS using selected ion monitoring and the standard addition method. The content of diphenidine in the herbal product was as high as 289 ± 23.2 mg/g ( n = 5); that of 5-fluoro-AB-PINACA was 55.5 ± 5.8 mg/g ( n = 3). Diphenidine is known as an N -methyl- d -aspartate receptor channel blocker. Although its human toxicity has not been studied, it is likely to have severe psychotropic action in humans. The very high content of diphenidine in the present herbal package should prompt law enforcement agencies to be aware of the potential harmful effects of diphenidine itself and also when consumed in combination with other drugs of abuse.
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Journal of Nanostructure in Chemistry
·
2014
·Vol. 4
·期 3
·1-8
·
IF 0
Li Lihua,Feng Dexiang,Fang Xian,Han Xiaowei,Zhang Yuzhong
In this work, we have developed a novel visual Hg 2+ sensor in aqueous solution using unmodified Au@Ag core–shell nanoparticles at room temperature, based on a redox reaction between Ag-shell and Hg 2+ . The prepared Au@Ag core–shell nanoparticles exhibited good monodispersity. In the presence of Hg 2+ , Hg 2+ was reduced into Hg (0) by Ag-shell, and deposited on the surface of Au-core to form Au–Hg alloys and caused nanoparticles aggregation, leading to the color changes of the solution from yellow to purplish red, and the surface plasmon resonance spectra of Au@Ag core–shell nanoparticles red shift. Under the optimal conditions, the visual sensor could selectively detect Hg 2+ as low as 0.4 µM with the naked eye and 5.0 nM by UV–vis spectra analysis methods. The designed sensor had several advantages: (1) the nanoparticles surface need not be functionalized. (2) The color change of the solution was in 2 s and could easily be observed with naked eyes. The visual sensor had been applied to detection of Hg 2+ in tap and lake water, which obtained satisfied result.
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CHROMATOGRAPHIA
·
2014
·Vol. 77
·期 19
·1379-1386
·
IF 1.37
Liu Huijun,Li Caixia,Wang Hong,Huang Zhongping,Zhang Peipei,Pan Zaifa,Wang Lili
Headspace solid-phase microextraction and gas chromatography/mass spectrometry (HS-SPME–GC/MS) method combined with XCMS Online was tentatively applied to characterize the dysregulated volatile organic metabolites (VOMs) in benign and malignant pleural effusions. A total of 9 dysregulated feature groups were isolated from metabolic features in 35 pleural effusion samples (20 benign effusions and 15 malignant ones from lung cancer patients). Principle component analysis, partial least squares discriminant analysis (PLS-DA) and orthogonal PLS-DA were built to separate benign from malignant pleural effusion groups and to find dysregulated metabolites in significantly different amounts between the two groups. Four dysregulated VOMs such as 2-ethyl-1-hexanol, cyclohexanone, 1,2,4,5-tetramethylbenzene and naphthalene were selected according to the variable influence on the projection value. The concentration of the four dysregulated VOMs in benign and malignant effusions were further determined by external standard method. The median concentrations of 4 VOMs in malignant effusion samples were from 4.7 to 91,121.9 nM, whereas their median levels were only 1.9–318.3 nM in benign ones. The results show that the proposed SPME–GC/MS-based metabolomic approach combined with XCMS Online data processing is a simple, rapid and available method for the characterization of dysregulated VOMs in malignant and benign pleural effusions.
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Optoelectronics Letters
·
2014
·Vol. 10
·期 3
·164-167
·
IF 0
Yang Ai-ling,Li Shun-pin,Wang Yu-jin,Bao Xi-chang,Yang Ren-qiang
By adjusting pH values of reactant system, the mass ratio of stabilizer/water and aging temperature, size controllable spherical silver nanoparticles (NPs) were synthesized. The properties of silver NPs are characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet visible (UV-VIS) absorption spectra. Within the pH values of 7.0–11.0, the aging temperature of 80 °C is better to improve silver NPs in shape to nearly sphere, concentrate size distribution and reduce aggregation than the aging temperature of 25 °C. The shape and dispersibility of silver NPs are the best when the pH of the reactant system is within 7.0–8.0. With pH of 7.5, aging at 80 °C, and stabilizer/water mass ratio of 1%, the spherical silver NPs with sizes of 50–70 nm were synthesized. The results are promising to be used to synthesize core/shell NPs when silver NPs are as core.
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JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
·
2014
·
IF 3.193
Konstantin Chingin,Ning Xu,Huanwen Chen
The charge states of biomolecular ions in ESI-MS can be significantly increased by the addition of low-vapor supercharging (SC) reagents into the spraying solution. Despite the considerable interest from the community, the mechanistic aspects of SC are not well understood and are hotly debated. Arguments that denaturation accounts for the increased charging observed in proteins sprayed from aqueous solutions containing SC reagent have been published widely, but often with incomplete or ambiguous supporting data. In this work, we explored ESI MS charging and SC behavior of several biopolymers including proteins and DNA oligonucleotides. Analytes were ionized from 100 mM ammonium acetate (NH4Ac) aqueous buffer in both positive (ESI+) and negative (ESI–) ion modes. SC was induced either with m-NBA or by the elevated temperature of ESI capillary. For all the analytes studied we, found striking differences in the ESI MS response to these two modes of activation. The data suggest that activation with m-NBA results in more extensive analyte charging with lower degree of denaturation. When working solution with m-NBA was analyzed at elevated temperatures, the SC effect from m-NBA was neutralized. Instead, the net SC effect was similar to the SC effect achieved by thermal activation only. Overall, our observations indicate that SC reagents enhance ESI charging of biomolecules via distinctly different mechanism compared with the traditional approaches based on analyte denaturation. Instead, the data support the hypothesis that the SC phenomenon involves a direct interaction between a biopolymer and SC reagent occurring in evaporating ESI droplets.
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