JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
·
2019
·Vol. 30
·期 6
·1203-1210
·
IF 1.335
Ge Dandan,Wang Ying,Jiang Qian,Dai Enrui
In this study, an in situ deep eutectic solvent-liquid-liquid microextraction method together with high performance liquid chromatography was developed for the determination of parabens in aqueous sample. The hydrophobic deep eutectic solvent, formed in situ by the DL-menthol and decanoic acid was used as the extraction solvent. Various parameters affecting the extraction efficiency including the composition of deep eutectic solvent, temperature of sample solution, extraction time, solution pH and salt concentration were investigated and optimized. Under the optimum conditions, the linear range of calibration curves was in the range of 3-1000 ng mL-1. The limits of detection and limits of quantification were in the range of 0.6-0.8 and 2.0-2.5 ng mL-1, respectively. The relative standard deviations were less than 7.2% for both intra-day and inter-days analysis. Finally, the proposed method was successfully applied to determine four parabens in environmental water samples with acceptable recoveries.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2019
·
IF 0
Qin Dai,He Zhao,Hongbin Cao,Yiqiu Wu,Zhi Sun,Xiaofei Meng,Tianyu Wang,Guangfei Yu,Jingyi Lin,Rong Hou
The green and low-cost preparation of carbon dots (CDs) with excellent fluorescence plays a key role in cell-imaging applications. Herein, we develop a green photochemical approach for fabricating CDs. The produced CDs can be used directly in lung cancer A549 cell imaging without any tedious post-treatments. As nontoxic and green alternatives to prevent pollution, fatty acids in sole aqueous media are the only reactants used to synthesize CDs. Furthermore, the green process of photoirradiation avoids harsh conditions, such as strong acids and bases, strong oxidants, and high temperatures and pressures. In addition, the by-products remaining in the aqueous environment are fatty acid dimers in the form of vesicles, which can also be recycled as gemini surfactant resources. We demonstrate that this green synthetic method for fabricating CDs is suitable for fatty acids with different chain lengths, and therefore, exhibits considerable universality. Fatty acids, as readily available green resources in nature, and the green and simple synthesis method without additional pollution provides a new approach and perspective for the green synthesis of CDs for bioimaging.
✓ 已验证
产品关联
DOI
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 35
·20317-20324
·
IF 10.733
Hongjian Wang,Long Chen,Hao Yang,Meidi Wang,Leixin Yang,Haiyan Du,Chenliang Cao,Yanxiong Ren,Yingzhen Wu,Fusheng Pan,Zhongyi Jiang
Covalent organic frameworks (COFs) hold great promise in molecular separation. However, since the aperture size of most COFs is in the range of 0.8–4.9 nm, constructing COF membranes with a smaller aperture size is thus in urgent demand yet remains a grand challenge. In this study, a Brønsted acid mediated one-step self-assembly method for the fabrication of COF membranes is proposed by segregating the organic phase (containing Brønsted acids and aldehydes) from the aqueous phase (containing amines) with a polymeric support and implementing an interfacial polymerization reaction thereby. Brønsted acids, serving as a versatile mediator, can facilitate the amorphous-to-crystalline transformation, ensure the confined membrane growth at the interface and regulate the assembly behavior of COF subunits, and thus play a critical role in manipulating the microstructure evolution of COF-JLU2 membranes. More intriguingly, a correlation among membrane structures, separation performance and the partition coefficient (log P) of Brønsted acids was established. When log P lies in between 1.0 and 3.0, the COF membranes with continuous active layers, tunable thickness (50–400 nm) and small aperture size (0.49–0.51 nm) can be fabricated, achieving superior alcohol dehydration performances to all the reported membrane counterparts. Our findings may stimulate further research on bottom-up construction of COF membranes and other kinds of organic framework membranes (XOF membranes).
✓ 已验证
产品关联
DOI
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2019
·
IF 4.527
Dezhi Yang,Yingdong Wang,Jianbo Peng,Chun Xun,Yaling Yang
A simple, effective and convenient method for determination of phenolic compounds by acid-base induced deep eutectic solvents (DESs) microextraction was developed. The binary and ternary DESs were prepared by a range of fatty acids (C 8 -C 12 ), which can act as hydrogen bond donors and hydrogen bond acceptors simultaneously. The gas-assisted mixing customization provides excellent mixing performance and concentration efficiency through the bubble adsorption mechanism for the handling of large-volume aqueous sample. In extraction process, NH 3 ·H 2 O can act as the emulsifier agent and reacted with DESs to form salts with a cloudy solution, which can obviously improve the extraction efficiency. HCl can act as the phase separation agent, and there is no need to centrifuge, which increases the efficiency of analysis procedure. The factors affected on extraction efficiency were carefully optimized. At optimum conditions and molar ratio of C 8 :C 9 :C 12 (3:2:1), the limit of detections (LODs), the preconcentration factor, the repeatability (RSDs%) were in the range of 0.22–0.53 μg L −1 , 235–244, and 2.6–6.7%, respectively. Finally, the proposed method was applied to analyze four phenolic compounds in real water samples and the recoveries were between 87.4% and 106.6%.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Jiaqi Wen,Yunguang Lu,Longyan Shi,Yaling Yang
A fatty acid deep eutectic solvent (DES) based cloud point extraction (DES-CPE) coupled with high-performance liquid chromatography (HPLC) to determine ultraviolet absorbent (UV) in food packaging bags was presented. In this DES-CPE method, DESs prepared from medium-chain saturated fatty acids (C 8 -C 12 ) and menthol are pH-dependent phase, and acid-base reactions can be carried out solely by adjusting the pH of the solution. The reaction conditions and extraction conditions, such as pH value, speed and time of vortex, selection and dosage of the extraction solvent, reaction time and temperature, effects of salt addition and centrifugation time were investigated in detail. Under optimal condition, the proposed method showed good linear range from 1 to 100μgmL −1 , with good assuming regression coefficients ( R 2 ) ≥ 0.997. The limit of detection (LODs), the quantitation (LOQs), the repeatability (RSDs%) were in the range of 0.05–0.17 μgmL −1 , 0.18–0.52 μgmL −1 , 0.93–2.65%, respectively. The enrichment factor was 10 and the recoveries of three Ultraviolet absorbents were between 82.2% and 103.4%.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2020
·
IF 1.701
Shengfu Duan,Yajie Jiang,Tao Geng,Hongbin Ju,Yakui Wang
In this paper, a series of methyltriphenylphosphonium carboxylate room temperature ionic liquids [Ph3PCH3][CnH2n+1COO] with different alkyl chain length (n = 7, 9, 11, 13, 15, 17) have been synthesized by quaternization of triphenylphosphine (TPP) with dimethyl carbonate (DMC) and followed anion exchange with different carboxylic acids. The synthesis route is not only simple, but also can avoid problems such as toxicity, environmental pollution and equipment corrosion. The structures of these compounds were characterized by FT-IR and 1H-NMR. Meanwhile, their surface adsorption and aggregation behavior in aqueous solution have been investigated by equilibrium surface tension, electrical conductivity and transmission electron microscopy (TEM) measurements. Furthermore, the impact of alkyl chain length on their surface adsorption and aggregation behavior were also investigated. TEM results indicated that methyltriphenylphosphonium carboxylate ionic liquid surfactants could self-assemble into regular spherical aggregates in aqueous solution. The diameter of the spherical aggregates is about 50 ∼ 100 nanometers and does not change much with the change of alkyl chain length.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Lihua Zhou,Yang He,Shaohua Gou,Qin Zhang,Ling Liu,Lan Tang,Xianzhi Zhou,Ming Duan
Currently, it remains a great challenge to maintain clay stability in water and prevent shear dispersion of the clay lamellae. Herein, a series of piperazine-based polyether Gemini quaternary ammonium salts (QAs) with different alkyl chains and linker groups were synthesized as the novel intercalator candidates. We established the correlations between their structures and inhibition swelling behavior of montmorillonite (MMT), a representatively hydratable and expansive clay. Upon loading saturated QAs, the lateral bilayer intercalation aligning parallelly to lamella surface was validated by X-ray diffraction (XRD), namely a monolayer adsorption on MMT platelets, agreeing well with Langmuir isotherm model. By combining Fourier transform infrared (FT-IR) spectroscopy and zeta potential, electrostatic attraction and hydrogen bonding were confirmed as the crucial multiple driving forces of adsorption and intercalation. The increased water contact angles (WCAs) demonstrated the formation of protective coating for hindering the entrance of water into the interlayers of MMT. XRD and field emission scanning electron microscope (FE-SEM) indicated that, when the carbon number of “tail” groups in QAs molecules was greater than 12, the platelets of organo-MMT (OMMT) were prone to be exfoliated and aggregated parallelly to sheet surface. This study provides a unique foundation for designing the molecular structure of clay modifier.
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2019
·
IF 5.714
Mei Huang,Yan Wang,Jinquan Wan,Yongwen Ma,Haiyuan Chi,Yanyan Xu,Shuying Qiu
Achieving large pore size, high catalytic performance with stable structure is critical for metal–organic frameworks (MOFs) to have more hopeful prospects in catalytic applications. Herein, we had reported a method to synthesize highly reactive yet stable defective iron-based Metal organic frameworks by using different monocarboxylic acids with varying lengths as a modulator. The physical−chemical characterization illustrating that modulators could improve the crystallinity , enlarge pore size and enhance catalytic performance and octanoic acid (OA) was screened to be the suitable choice. The catalytic performance of catalysts was detected through persulfate (PS) activation for degrading Tetrabromobisphenol A (TBBPA). The study demonstrated that the highest degradation efficiency for 0.018 mmol L −1 TBBPA was that 97.79% in the conditions of the 1.0 g L −1 Fe(BDC)(DMF,F)-OA-30 dosage and TBBPA:PS = 200:1. In addition, there was observed that no obvious change of the crystal structure, little the leachable iron concentration in the solutions and no significant loss of catalytic activities of Fe(BDC)(DMF,F)-OA-30 after 5th cycles. The iron valence state of Fe(BDC)(DMF,F)-OA-30 before and after degradation and electrochemical properties reveal that the partial substitution of organic ligands by octanoic acid, when removing OA and forming defects by heat and vacuum treatment to generate coordinatively unsaturated metal sites and accelerate the original transmission of electronic, leading to enhance the activity of persulfate activation for efficient removal TBBPA.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD PROCESSING AND PRESERVATION
·
2019
·Vol. 43
·期 8
·e14003
·
IF 1.288
Zhong-Sheng Tang,Xin-An Zeng,Margaret A. Brennan,Zhong Han,Debao Niu,Yujia Huo
Characteristic aroma substances of cis-rose oxide imparts the odorant of “lychee-like,” while of citronellol is the precursor of it in lychee. The characterization of volatiles of lychee wine fermentation using headspace solid-phase microextraction gas chromatography-mass spectrometry combined with headspace gas chromatography-ion mobility spectrometry were done to regulate processing. Results indicated that the total of 97 volatiles (38 in common) were observed during fermentation, including 39 terpenoids, 5 alcohols, 22 esters, 4 acids, 7 alkenes, 4 ketones and ethers, 3 sulfur compounds and others. Losses of characteristic aromas mainly occurred during primary fermentation more than threefold decrease. The volatility of cis-rose oxide was stronger than citronellol, which implied that more gentle processing should be performed to protect lychee flavor. Cis-rose oxide was a mixture of monomer and dimer with unequal proportion, while citronellol was a monomer in lychee. The work provides important new information on aroma development during fermentation. Practical applications Fruit consumption, among which tropical fruit-based products have gained huge popularity in the recent years. The main high value-added processed products of lychee pulp are lychee wine and vinegar; however, the typical aroma always decreased or disappeared during fermentation. Therefore, this study aims at providing more information for product improvement and process development.
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 5
·3091-3103
·
IF 3.809
Zhang Yanjuan,Wei Liping,Hu Huayu,Zhao Zengyan,Huang Zuqiang,Huang Aimin,Shen Fang,Liang Jing,Qin Yuben
Abstract Three cellulose esters, cellulose acetate-butyrate, cellulose acetate-octanoate, and cellulose acetate-laurate, were synthesized by both conventional co-reactant reaction (CCR) and mechanical activation-assisted co-reactant reaction (MACR) methods, and the corresponding nano-cellulose esters were prepared by high pressure homogenization to comparatively investigate their tribological properties as lubricant additives in liquid paraffin base oil. MACR method was more effective than CCR method for preparing long chain cellulose esters, and the MACR-prepared cellulose esters were more easily homogenized to smaller nanoparticles. Tribological testing indicated that anti-wear and load-carrying properties of the lubricants were significantly enhanced with nano-cellulose esters as additives compared to those of pure liquid paraffin, especially the MACR-prepared long chain cellulose esters. The wear scar diameter on worn surface of the steel balls reduced with the increase in degree of substitution (DS) and chain length of long chain substituents and the decrease in size dimension of nano-cellulose esters. The polar ester carbonyl groups, unesterified hydroxyl groups, and long hydrocarbon alkyl chains in nano-cellulose esters could lead to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear, which gave the lubricants with good anti-wear and load-carrying properties. The nano-cellulose esters with high DS and long chain substituents prepared by MACR technology as ecofriendly additives exhibited better lubricating ability. Graphical abstract Nano-cellulose esters with high DS of long chain substituents prepared by mechanical activation-assisted co-reactant reaction technology used as ecofriendly lubricant additives in base oil showed good anti-wear and load-carrying properties, ascribing to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear.
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES
·
2018
·
IF 3.466
Qiaoyun Li,Xiaocao Wan,Chao Liu,Liang Fang
The aim of this study was to prepare a drug-in-adhesive patch of nicotine (NIC) and use ion-pair strategy to regulate drug delivery rate. Moreover, the mechanism of how ion-pair strategy regulated drug release was elucidated at molecular level. Formulation factors including pressure sensitive adhesives (PSAs), drug loading and counter ions (C 4 , C 6 , C 8 , C 10 , and C 12 ) were screened. In vitro release experiment and in vitro transdermal experiment were conducted to determine the rate-limiting step in drug delivery process. FT-IR and molecular modeling were used to characterize the interaction between drug and PSA. Thermal analysis and rheology study were conducted to investigate the mobility variation of PSA. The optimized patch prepared with NIC-C 8 had the transdermal profile fairly close to that of the commercial product ( p > 0.05). The release rate constants ( k ) of NIC, NIC-C 4 and NIC-C 10 were 21.1, 14.4 and 32.4, respectively. Different release rates of NIC ion-pair complexes were attributed to the dual effect of ion-pair strategy on drug release. On one hand, ion-pair strategy enhanced the interaction between drug and PSA, which inhibited drug release. On the other hand, using ion-pair strategy improved the mobility of PSA, which facilitated drug release. Drug release behavior was determined by combined effect of two aspects above. These conclusions provided a new idea for us to regulate drug release behavior from patch.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2018
·Vol. 18
·期 12
·8124-8132
·
IF 1.354
Fan Dongxiao,Yao Chen,Zhou Wenya,Li Xinsong
To develop new antimicrobial synthetic lipopeptides with optimizing peptide length, cationic tripeptides RWR/WRR were N-terminal fatty acylated, and self-assembled with 1-dodecanethiol-anchored gold nanoparticles (Au-DT NPs) via hydrophobic interaction. The ultrashort lipopeptides and
their nano-assemblies were effective against a variety of microorganisms, with minimal inhibitory concentrations ranging from 0.5 to 8 μg/mL. Hemolysis analysis and in vitro cytotoxicity assay revealed that self-assembling with Au-DT NPs would improve biological toxicity of
lipopeptides, especially for the most active lipopeptides (Palmitoyl-RWR, Palmitoyl-WRR) with long lipid tails. As lipopeptides/ Au-DT NPs displayed slower bactericidal kinetics compared with free lipopeptides, the mode of action was further investigated. Difference in membrane targeting mechanism
between lipopeptides and their nano-assemblies may be attributed to the structural architecture. The simple composition and diverse specificities of lipopeptides/Au-DT NPs, as well as their biocompatibility could make them as economically available potent antimicrobial agents for various applications.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）