SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2019
·
IF 2.931
Jingwen Xiong,Zongzhi Li,Shaomin Ji,Chengqiang Pan,Wenjin Ji,Qi Li,Yanping Huo
Four novel highly selective 8-hydroxyquinoline-based fluorescent chemodosimeters ( 1 – 4 ) were synthesized for the rapid analysis of Hg 2+ in aqueous solution and on paper strips, which probably attributed to the excited state intramolecular proton transfer (ESIPT) process. Chemodosimeter 1 was evaluated as a Hg 2+ -ratiometric fluorescent sensor while others ( 2 , 3 and 4 ) displayed fluorescence turn-on response for Hg 2+ among the various survey metal ions . We demonstrated that chemodosimeters ( 1 – 4 ) could recognized Hg 2+ ions based on a 1:1 stoichiometric binding event with fast detection time. More importantly, the detection limits for Hg 2+ could reach at 10 −9 M level except chemodosimeter 1 (4.05 × 10 −8 M). In addition, it was found that chemodosimeters ( 1 – 4 ) were recycled efficiently because the Hg 2+ induced emission spectra were reversed after adding NaBH 4 . Finally, these four sensors were successfully applied for fabrication of simple device test strips for rapid and on-site detection of Hg 2+ ions.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
·
IF 6.393
Yuling Chen,Wei Huang,Kuijun Chen,Ting Zhang,Yang Wang,Jianmin Wang
Herein, a novel core-shell structure composite with traditional conducting polymer, polypyrrole (PPy) as its core and zeolitic imidazolate framework-8 (ZIF-8) shell structure was successfully prepared. Thanks to the advantages over electrocatalytic surface provided by ZIF-8 shell and a charge collector given by PPy, the obtained core/shell-structured PPy@ZIF-8 composite displayed an excellent electrocatalytic performance towards quercetin (QR) determination. Under the optimized experimental condition, the differential pulse voltammetry (DPV) peak current signals depend linearly on QR concentration in the range of 0.01–7.0 μmol ⋅ L −1 and 7.0–150 μmol ⋅ L −1 with a low detection limit of 7 nmol ⋅ L −1 . Furthermore, the proposed electrochemical sensor also exhibited good sensitivity, excellent selectivity with reasonable reproducibility and stability during the detection of quantitative QR. A satisfactory performance was observed when this novel sensor was applied to detect QR in human plasma samples with recoveries of 99.1–102.6% and R.S.D. (n = 3) < 3.2%. Thus, the current study provides a new and efficient electrocatalyst for designing QR electrochemical sensor based on conductive conjugated polymer/MOFs heterostructure.
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MOLECULES
·
2019
·Vol. 24
·期 22
·4038
·
IF 3.06
Huifang Liu,Lihua Jiang,Meng Lu,Guangyang Liu,Tengfei Li,Xiaomin Xu,Lingyun Li,Huan Lin,Jun Lv,Xiaodong Huang,Donghui Xu
A simple, sensitive and effective magnetic solid-phase extraction (MSPE) technique was developed for the extraction of pyrethroid pesticides from environmental water samples, followed by gas chromatography tandem triple quadrupole mass spectrometry determination. An adsorbent of magnetic zeolitic imidazolate framework-8@deep eutectic solvent (M-ZIF-8@DES) was prepared using deep eutectic solvent coated on the surface of M-ZIF-8. The features of M-ZIF-8@DES were confirmed by material characterizations, and the results indicated that M-ZIF-8@DES has a good magnetism (61.3 emu g−1), a decent surface area (96.83 m2g−1) and pore volume (0.292 mL g−1). Single factor experiments were carried out to investigate the effect of different conditions on the performance of MSPE. Under the optimal conditions, the developed method performs good linearity (R2≥ 0.9916) in the concentration range of 1–500 μg L−1. The limits of detection were in the range of 0.05–0.21 μg L−1(signal/noise = 3/1). The intraday relative standard deviation (RSD) and interday RSD were less than 9.40%. Finally, the proposed technique was applied for the determination of pyrethroid pesticides in environmental water samples. This work shows the potential of DES-modified metal-organic frameworks for different sample pretreatment techniques.Keywords:magnetic solid-phase extraction;zeolitic imidazolate framework;deep eutectic solvents;pyrethroids;environmental water
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MOLECULES
·
2019
·Vol. 24
·期 17
·3041
·
IF 3.06
Yanqing Liu,Gengxin Hu,Hongwu Wang,Su Yao,Yinjian Ye
A hybrid nanocomposite consisting of hydroxylated multi-walled carbon nanotubes (MWCNTs−OH) and cube mesoporous carbon (CMK−8) was applied in this study to construct an MWCNT−OH/CMK−8/gold electrode (GE) electrochemical sensor and simultaneously perform the electro-reduction of olaquindox (OLA) and carbadox (CBX). The respective peak currents of CBX and OLA on the modified electrode increased by 720- and 595-fold relative to the peak current of GE. The performances of the modified electrode were investigated with electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Then, the modified electrodes were used for the individual and simultaneous determination of OLA and CBX. The fabricated sensor demonstrated a linear response at 0.2–500 nmol/L in optimum experimental conditions, and the detection limits were 104.1 and 62.9 pmol/L for the simultaneous determination of OLA and CBX, respectively. As for individual determination, wide linear relationships were obtained for the detected OLA with levels of 0.05–500 nmol/L with LOD of 20.7 pmol/L and the detected CBX with levels of 0.10–500 nmol/L with LOD of 50.2 pmol/L. The fabricated sensor was successfully used in the independent and simultaneous determination of OLA and CBX in spiked pork samples.Keywords:CMK−8;MWCNTs−OH;electrochemical sensor;differential pulse voltammetry;simultaneous determination;carbadox;olaquindox
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Ying Lv,Dandan Ding,Yixi Zhuang,Yushuo Feng,Junpeng Shi,Hongwu Zhang,Tian-Liang Zhou,Hongmin Chen,Rong-Jun Xie
Multifunctional theranostic nanoplatforms greatly improve the accuracy and effectiveness in tumor treatments. Much effort has been made in developing advanced optical imaging-based tumor theranostic nanoplatforms. However, autofluorescence and irradiation damage of the conventional fluorescence imaging technologies as well as unsatisfied curative effects of the nanoplatforms remain great challenges against their wide applications. Herein, we constructed a novel core–shell multifunctional nanoplatform, that is, chromium-doped zinc gallogermanate (ZGGO) near-infrared (NIR) persistent luminescent nanoparticles (PLNPs) as a core and zeolitic imidazolate framework-8 (ZIF-8) as a shell (namely ZGGO@ZIF-8). The ZGGO@ZIF-8 nanoplatform possessed dual functionalities of the autofluorescence-free NIR PersL imaging as well as the pH-responsive drug delivery, thus it has high potential in tumor theranostics. Notably, the loading content of doxorubicin (DOX) in ZGGO@ZIF-8 (LC = 93.2%) was quite high, and the drug release of DOX-loaded ZGGO@ZIF-8 was accelerated in an acidic microenvironment such as tumor cells. The ZGGO@ZIF-8 opens up a new material system in the combination of PLNPs with metal–organic frameworks and may offer new opportunities for the development of advanced multifunctional nanoplatforms for tumor theranostics, chemical sensing, and optical information storage.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2018
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IF 3.779
Dashui Yuan,Jing Ding,Jie Zhou,Lei Wang,Hui Wan,Wei-Lin Dai,Guofeng Guan
A highly efficient ZIF-8/g-C 3 N 4 photocatalyst was prepared by a facile ultrasonic in-situ method. The structure-property relationship of ZIF-8/g-C 3 N 4 composite was analysed by various characterization techniques. The comprehensive study illustrated that ZIF-8 served as an adsorbent to capture the substrates in the contaminated solution and increased the contact possibilities of the active species and substrates. The formation of ZIF-8/g-C 3 N 4 hybrids helped to significantly enhance visible light absorption and facilitate charge transfer and separation of the photogenerated electron-hole pairs, eventually improving the photocatalytic efficiency. Meanwhile, compared with ZIF-8/g-C 3 N 4 composites obtained by incipient wetness impregnation method, ultrasonic in-situ synthesis contributed to hindering the aggregation of g-C 3 N 4 nanosheets and simultaneously promoting ZIF-8 well dispersed on the surface of g-C 3 N 4 nanosheets. The synergistic effect of preparation method and special hybrid structure was studied in-depth and could significantly enhanced photocatalytic activity and stability for the degradation of organic pollutants (such as tetracycline, rhodamine B and methyl orange) under visible light irradiation. The reaction rate constant K values of optimal ratio sample for degradation of TC, RhB and MO were 0.039 min −1 , 0.034 min −1 and 0.012 min −1 , respectively 1.69, 3.96 and 4.10 times as big as that of pure g-C 3 N 4 . Meanwhile, the photoresponse current of optimal ratio sample was 3.3 μA/cm 2 , around 4.73 times as big as that of the pure g-C 3 N 4 . A reasonable photocatalytic mechanism was proposed by the photoelectrochemical experiments and the controlled experiments using radical scavengers.
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Polymers
·
2018
·Vol. 10
·期 10
·1089
·
IF 2.935
Lili Liu,Xiaojing Zhou,Yongmei Yan,Jie Zhou,Wenping Zhang,Xishi Tai
The metal-organic zeolite imidazolate framework-8 (ZIF-8) supported gold-silver bimetallic catalysts with a core-shell structure (Au@Ag/ZIF-8 and Ag@Au/ZIF-8) and cluster structure (AuAg/ZIF-8) were successfully prepared by the deposition-redispersion method. Energy dispersive X-ray spectroscopy (EDS) elemental mapping images displayed that in the Au@Ag/ZIF-8 catalyst, Ag atoms were deposited on an exposed Au surface, and core-shell structured Au@Ag particles with highly dispersed Ag as the shell were formed. Additionally, the XPS investigation at gold 4f levels and silver 3d levels indicated that the Au and Ag particles of Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were in a zero valence state. Among the resultant catalysts obtained in this study, Ag@Au/ZIF-8 catalysts showed the highest catalytic activity for the selective oxidation of benzyl alcohol, followed by AuAg/ZIF-8 and Au@Ag/ZIF-8. The turnover frequency (TOF) values were in the order of Ag@Au/ZIF-8 (28.2 h−1) > AuAg/ZIF-8 (25.0 h−1) > Au@Ag/ZIF-8 (20.0 h−1) at 130 °C within 1 h under 8 bar O2when using THF as solvent. The catalysts of Au@Ag/ZIF-8 and Ag@Au/ZIF-8 with core–shell structures have higher benzaldehyde selectivities (53.0% and 53.3%) than the AuAg/ZIF-8 catalyst (35.2%) in the selective oxidation of benzyl alcohol into benzaldehyde. The effect of the solvent, reaction temperature, reaction time, and reaction pressure on benzyl alcohol conversion and benzaldehyde selectivity in benzyl alcohol selective oxidation over Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were also investigated. All of the catalysts showed excellent performance at 130 °C under 8 bar O2within 1 h when using THF as the solvent in the selective oxidation of benzyl alcohol to benzaldehyde. Moreover, the catalysts can be easily recycled and used repetitively at least four times.Keywords:metal-organic frameworks;core-shell;bimetallic catalyst;aerobic oxidation;benzyl alcohol
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Catalysts
·
2018
·Vol. 8
·期 5
·188
·
IF 3.465
Dalei Sun,Kaihong Xie,Yanxiong Fang,Xianghua Yang
One-pot synthesis ofN,N′-dialkylureas were successfully achieved from catalytic carbonylation of aliphatic primary amines with CO2as the carbon source and Y0.08Zr0.92O1.96mixed oxide (Yttria-stabilized zirconia, YSZ-8) as the heterogeneous catalyst. The yield of the target product was obtained up to 80.60% from a 48 h reaction with an aliphatic primary amine and 3.0 MPa CO2inN-methyl-2-pirrolidinone at 160 °C. A multi-pronged mechanistic study was carried out where factors that might influence the reaction efficiency were studied, including catalyst structure, substrates basicity, CO2pressure, solvent polarity and reaction time. The presence of oxygen vacancies in YSZ-8 was found to be essential for the carbonylation process by creating additional reduction potential for the activation of CO2which would lead to the key intermediate species.Keywords:Y0.08Zr0.92O1.96mixed oxide;N,N′-dialkylurea;carbonylation;CO2;heterogeneous catalysis
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RSC Advances
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2018
·Vol. 8
·期 72
·41368-41375
·
IF 2.936
Liangliang He,Jinjin Xu,Qi Wang,Yezi Zhang,Zifei Qin,Yang Yu,Zhengming Qian,Zhihong Yao,Xinsheng Yao
Shogaols, mainly [6]-shogaol (6S), [8]-shogaol (8S) and [10]-shogaol (10S), the predominant and characteristic pungent phytochemicals in ginger, are responsible for most of its beneficial effects. However, poor oral bioavailability owing to extensive glucuronidation limits their application. The present study aimed to characterize the glucuronidation pathways of 6S, 8S and 10S by using pooled human liver microsomes (HLM), human intestine microsomes (HIM) and recombinant human UDP-glucosyltransferases (UGTs). The rates of glucuronidation were determined by incubating shogaols with uridine diphosphate glucuronic acid-supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. Reaction phenotyping assays, activity correlation analyses and relative activity factors were performed to identify the main UGT isoforms. As a result, one mono-4′-O-glucuronide was detected after incubating each shogaol with HLM and HIM. Enzymes kinetic analysis demonstrated that glucuronidation of shogaols consistently displayed the substrate inhibition profile, and the liver showed higher metabolic activity for shogaols (CLint = 1.37–2.87 mL min−1 mg−1) than the intestine (CLint = 0.67–0.85 mL min−1 mg−1). Besides, reaction phenotyping assays revealed that UGT2B7 displayed the highest catalytic ability (CLint = 0.47–1.17 mL min−1 mg−1) among all tested UGTs. In addition, glucuronidation of shogaols was strongly correlated with AZT glucuronidation (r = 0.886, 0.803 and 0.871 for glucuronidation of 6S, 8S and 10S, respectively; p < 0.01) in a bank of individual HLMs (n = 9). Furthermore, UGT2B7 contributed to 40.8%, 34.2% and 36.0% for the glucuronidation of 6S, 8S and 10S in HLM, respectively. Taken altogether, shogaols were efficiently metabolized through the glucuronidation pathway, and UGT2B7 was the main contributor to their glucuronidation.
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JOURNAL OF HETEROCYCLIC CHEMISTRY
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2014
·Vol. 51
·期 4
·1094-1099
·
IF 0.873
Guangfan Han,Jiawei Du,Lizhuang Chen,Lijun Zhao
A series of 2-amino-7-methoxy-4-aryl-4 H -chromene-3-carbonitrile compounds 2 were obtained by condensation of 3-methoxyphenol with β-dicyanostyrenes 1 in absolute ethanol containing piperidine. The intermediate enamines 3 were prepared by compounds 2 with 5-substituted-1,3-cyclohexanedione using p -toluenesuflonic acid (TsOH) as catalyst. The title compounds 11-amino-3-methoxy-8-substituted-12-aryl-8,9-dihydro-7 H -chromeno[2,3- b ]quinolin-10(12 H )-one 4 were synthesized by cyclization of the intermediate enamines 3 in THF with K 2 CO 3 /Cu 2 Cl 2 as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1 H NMR spectra. The crystal structure of compound 4i was determined by single-crystal X-ray diffraction analysis.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
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IF 2.206
Jiangfeng Yang,Junmin Li,Wei Wang,Libo Li,Jinping Li
Three hydrophobic microporous high-silica zeolites, DDR (with an 8-membered ring), silicalite-1 (a 10-membered ring), and beta (a 12-membered ring) were synthesized. The Si/Al ratios were 230, 1350, and 35, respectively. The samples were characterized by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, water vapor adsorption, and volumetric nitrogen adsorption. They were tested for their CO2, CH4, and N2 adsorption properties at pressures of up to 10 bar at 288–313 K after activation, and the results were correlated with the Langmuir model. The heat of adsorption was calculated using the Clausius–Clapeyron equation based on the adsorption isotherms. These data were used to estimate the separation selectivities for CO2/CH4 and CH4/N2 binary mixtures at 298 K, using the ideal adsorbed solution theory (IAST) model. Experimental results showed that DDR and beta have good selectivities for CO2/CH4, because they have narrow pores (DDR) or more balance metal ions (relatively low Si/Al ratios beta) effect separately. The synthesized silicalite-1 has the lowest SCO2/CH4 but has the most suitable orifices for methane adsorption and the highest SCH4/N2. In addition, the breakthrough data for CH4/N2 mixtures further indicates that silicalite-1 is more suitable for the CH4 enrichment than the commercially used sorbents zeolite-5A and 13X. From the reproducibility of CH4 and N2 adsorption isotherms on silicalite-1, we can infer that which has the potential to be a commercial sorbent by the stable adsorption properties.
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PHARMACEUTICAL BIOLOGY
·
2015
·
IF 1.241
Nian-Gui Xu,Zhi-Jie Xiao,Ting Zou,Zhi-Ling Huang
Context: Polygonum cuspidatum Sieb. Et Zucc. (Polygonaceae) has been traditionally used in folk medicine to treat various diseases.Objective: This study investigates the ameliorative effects of physcion 8-O-β-glucopyranoside (PSG) isolated from P. cuspidatum on learning and memory in dementia rats induced by Aβ1–40.Materials and methods: Dementia rats were prepared by intracerebroventricular injection of Aβ1–40. PSG (5, 10, 20, and 40 mg/kg/d, for 5 d) was administered orally. Ameliorative activity of PSG in dementia rats was evaluated by the Morris water maze (MWM) test, and its mechanisms were explored by evaluating AchE activity, levels of DA, NE, and 5-HT in hippocampus, and drebrin protein expressions in hippocampus.Results: Our results indicated that PSG (5, 10, 20, and 40 mg/kg/d) significantly inhibited the prolonged latency in dementia rats (p < 0.05), and inhibitory rates were 16.5, 22.7, 33.0, and 44.8% after 5 d of learning, indicating that PSG improves learning and memory of dementia rats. Furthermore, PSG significantly decreased AchE activity (10, 20, and 40 mg/kg/d; p < 0.05), increased 5-HT (20 and 40 mg/kg/d, p < 0.05), NE (10, 20, and 40 mg/kg/d; p < 0.05), and DA levels (5, 10, 20, and 40 mg/kg; p < 0.05) in the hippocampus. Additionally, PSG obviously decreased the Aβ contents in hippocampus (10, 20, and 40 mg/kg/d; p < 0.05), and up-regulated drebrin protein expressions (5, 10, 20, and 40 mg/kg/d; p < 0.05).Conclusions: PSG can significantly enhance learning and memory in Aβ1–40-induced dementia rats, and the mechanisms may be related to increase levels of Ach, 5-HT, NE, and DA, decrease Aβ contents, and up-regulation of drebrin proteins in hippocampus.
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