JOURNAL OF SEPARATION SCIENCE
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2019
·Vol. 42
·期 18
·2957-2967
·
IF 2.516
Xintong Jia,Xiaoyue Yang,Wei Zhao,Yuanan Hu,Hefa Cheng
Driven by the significant need for characterization of the chemical speciation of arsenic in food, this work developed a method for rapid determination of four common arsenic species, namely, arsenite, arsenate, monomethyl arsenic acid, and dimethyl arsenic acid, in vegetables using microwave-assisted extraction, followed by detection with high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry. Initial screening results showed that microwave-assisted extraction using 1% HNO 3 exhibited the highest overall efficiencies for all arsenic species without causing significant degradation of the organic ones. With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500 mg of freeze-dried vegetable sample, extracted by closed vessel microwave-assisted extraction using 10 mL of 2% v/v HNO 3 at 90°C for 17 min. Application of the method in the analysis of 24 market vegetable samples indicates that the extraction efficiencies for total arsenic species were in the range of 91.4–106%. Arsenite and arsenate were found to be the predominant arsenic species in the vegetables, which suggests that vegetable consumption could be an important route of inorganic arsenic exposure for the population with a heavy vegetable diet in arsenic polluted regions.
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Materials
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2019
·Vol. 12
·期 10
·1583
·
IF 2.972
Zhen Li,Libo Yu
Size controllable TiO2hollow microspheres (HMS) were synthesized by a carbonaceous spheres (CS) template method. Based on TiO2HMS, the ZnS/CdS quantum dots (QDs) were loaded to form a ZnS/CdS@TiO2HMS photoanode for quantum dots sensitized solar cell (QDSSC). The size effects of TiO2HMS on photovoltaic performance were investigated, and showed that TiO2HMS with sizes ~560 nm produced the best short-circuit current density (Jsc) of 8.02 mA cm−2and highest power conversion efficiency (PCE) of 1.83%, showing a better photovoltaic performance than any other QDSSCs based on TiO2HMS with size ~330 nm, ~400 nm, and ~700 nm. The improvement of photovoltaic performance based on ~560 nm TiO2HMS which can be ascribed to the enhanced light harvesting efficiency caused by multiple light reflection and strong light scattering of TiO2HMS. The ultraviolet-visible (UV-vis) spectra and incident photo to the current conversion efficiency (IPCE) test results confirmed that the size of TiO2HMS has an obvious effect on light harvesting efficiency. A further application of ~560 nm TiO2HMS in ZnS/PbS/CdS QDSSC can improve the PCE to 2.73%, showing that TiO2HMS has wide applicability in the design of QDSSCs.Keywords:titanium dioxide;hollow microspheres;quantum dots sensitized solar cells
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2019
·Vol. 411
·期 17
·3979-3988
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IF 3.286
Qu Fei,Ding Yanru,Lv Xiaoxia,Xia Lian,You Jinmao,Han Wenli
Herein, a universal and multifunctional fluorescence sensor platform is designed by the interaction of aggregation/dispersion gold nanoparticles (AuNPs) with Tb-metal–organic frameworks (Tb-MOFs). It is found that the dispersed AuNPs rather than the aggregated ones can quench effectively the fluorescence of Tb-MOFs, and the quenching process presumably involves the mechanism of inner filter effect (IFE), dynamic quenching effect (DQE), and fluorescence resonance energy transfer (FRET). The different affinities of aptamer and aptamer–target complex toward AuNPs are employed to modulate the fluorescence signal change of Tb-MOFs. As the proof of concept, prostate-specific antigen (PSA), an efficient tumor indicator for prostate cancer, is selected as the target. At first, the PSA aptamer can protect AuNPs against salt-induced aggregation, leading to the fluorescence of Tb-MOFs quenching. Subsequently, upon PSA introduction, the rigid aptamer–PSA complex is formed and cannot stabilize AuNPs in high salt conditions, so the AuNPs aggregate significantly and the fluorescence of Tb-MOFs is restored. The linear range of PSA is achieved from 1 to 100 ng/mL with a detection limit of 0.36 ng/mL. Finally, this method has been validated to be sensitive and specific for PSA in human urine samples.
Graphical abstract
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NEUROGASTROENTEROLOGY AND MOTILITY
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2019
·Vol. 31
·期 5
·e13556
·
IF 3.803
Yong Li,Tingting Yang,Qing Yao,Songsong Li,En Fang,Yankun Li,Chao Liu,Weimin Li
Background Intestinal barrier dysfunction is a key etiologic factor of irritable bowel syndrome (IBS). Metformin improves intestinal barrier function, although the underlying mechanism has yet to be fully explained. This study evaluates the protective effect of metformin on colonic barrier integrity and explores the underlying cellular mechanisms. Methods IBS-like rats were induced by maternal separation. Metformin was administered daily by gavage at 08:30, and rat pups were then separated from their mother. Visceral hyperalgesia and depression-like behaviors were evaluated by colorectal distension, sucrose preference tests, and forced swimming tests. Intestinal integrity was analyzed using sugar probes and transmission electron microscopy. Inflammatory factors and the levels of corticotropin-releasing factor were assessed by PCR and ELISA. The number of mast cells was evaluated by toluidine blue staining. Protein expression and localization were determined using Western blot and immunochemistry. Key Results Metformin pretreatment (a) reduced visceral hypersensitivity to colorectal distension, immobility time and enhanced sucrose consumption; (b) decreased urine lactulose/mannitol ratio and sucralose output; (c) inhibited the dilation of tight junction and prevented claudin-4 translocation; (d) inhibited mast cell activation and downregulated the expression of IL-6, IL-18, tryptase, PAR-2, and ERK activation; (e) inhibited claudin-4 phosphorylation at serine sites and interactions between clau-4 and ZO-1. Conclusions & Inferences Metformin may block mast cell activation to reduce PAR-2 expression and subsequently inhibit ERK activation and clau-4 phosphorylation at serine sites to normalize the interaction of clau-4 and ZO-1 and clau-4 distribution. Metformin may be clinically beneficial for patients with IBS or IBS-like symptoms.
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高影响因子
SENSORS
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2019
·Vol. 19
·期 3
·674
·
IF 3.031
Hong Zhai,Yunfeng Bai,Jun Qin,Feng Feng
A novel colorimetric and ratiometric fluorescence sensor was constructed by using carbon quantum dots (CQDs) and o-diaminobenzene (ODB). Unlike ODB by itself, ODB oxide (oxODB) not only emits fluorescence, but also produces ultraviolet (UV) absorption. Therefore, on the basis of the potential optical properties of ODB, glucose oxidase (Gox) and horseradish peroxidase (HRP) were introduced into a CQDs–ODB system for the quantitative oxidation of ODB. When glucose is present, it is oxidized by oxygen under the catalytic action of its oxidase to form hydrogen peroxide. Hydrogen peroxide is a strong oxidant that can rapidly oxidize ODB through the catalysis of horseradish peroxidase. oxODB can cause changes in the fluorescence ratio (I550/I446) and absorbance ratio (A/A0). At the same time, the color of the detection solution can also change under sunlight and ultraviolet lamps. Therefore, glucose can be quantitatively detected by ratiometric fluorescence and colorimetry simultaneously, and semi-quantitatively detected by observing the colors with sunlight and ultraviolet lamps of 365 nm. This increases not only the convenience but also the accuracy of detection. In addition, this sensor has good selectivity and can be used for the determination of glucose in serum, providing a new idea for the development of blood glucose sensors.Keywords:dual-mode sensor;carbon quantum dots;o-diaminobenzene;glucose
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Weidong Zhao,Yun Zhu,Litong Zhang,Yunlong Xie,Xiangrong Ye
Porous activated carbon (PAC) with three-dimensionally (3D) interconnected structure has been successfully synthesized using sucrose and potassium hydroxide as carbon source and pore-forming agent, respectively. On account of its hierarchically porous structure and high specific surface area (1615 m 2 g −1 ), the synthesized porous carbon displays a maximal specific capacitance of 119 F g −1 at 1 A g −1 and a capacitance retention rate of 81.2% after 5000 cycles at 20 A g −1 in 1 M TEABF 4 /AN electrolyte. It also exhibits a maximal specific capacitance of 178 F g −1 at 0.5 A g −1 and a capacitance retention rate of 88.9% after 10000 cycles at 16 A g −1 in 1 M Na 2 SO 4 electrolyte. Moreover, the fabricated symmetric supercapacitor reveals a high energy density , 16.52 W h Kg −1 in 1 M TEABF 4 /AN and 15.78 W h Kg −1 in 1 M Na 2 SO 4 . Such an excellent supercapacitive performance implies that the prepared activated carbon with 3D interconnected porous structure could be potentially used for high performance energy storage device.
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MICROCHIMICA ACTA
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2019
·Vol. 186
·期 3
·1-8
·
IF 5.479
Liu Shi Gang,Luo Dan,Han Lei,Li Nian Bing,Luo Hong Qun
A hybrid material composed of guanine-rich single stranded DNA (G-rich ssDNA) and cobalt oxyhydroxide (CoOOH) nanosheets is used as a nanoprobe for fluorometric turn-on detection of ascorbic acid (AA). The CoOOH nanosheets function as a recognition component for AA. The G-rich ssDNA is used to produce a G-quadruplex, and the G-quadruplex/thioflavin T (ThT) complex acts as a fluorescent reporter. In the absence of AA, p-phenylenediamine (PPD) is oxidized to form oxPPD which has a dark red color. It causes the fluorescence of the G-quadruplex/ThT complex to be quenched. However, in the presence of AA, the CoOOH nanosheets of the nanoprobe are preferentially reduced by AA. Hence, PPD is not oxidized, and fluorescence is not quenched. A fluorometric turn-on method was developed based on these findings. It has a detection limit of 94 nM and works in the concentration range from 1 to 10 and 20 to 80 μM. This method was applied to the determination of AA in (spiked) fruit juice samples.
Schematic presentation of a fluorescent assay of ascorbic acid (AA) is established using a nanoprobe composed of guanine-rich single stranded DNA (G-rich ssDNA) and cobalt oxyhydroxide (CoOOH) nanosheets. It is based on competitive reduction of CoOOH by p-phenylenediamine (PPD) and AA. Thioflavine T (ThT) induces the formation of fluorescent G-quadruplex/ThT complex. The oxidized form of PPD (oxPPD) can quench the fluorescence via fluorescence resonance energy transfer (FRET), but AA suppresses quenching.
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Food Analytical Methods
·
2019
·Vol. 12
·期 5
·1086-1091
·
IF 2.413
Wu Zhengzong
Foodborne diseases arise from Listeria monocytogenes ( L. monocytogenes ) and Salmonella typhimurium ( S. typhimurium ) are global public health problems, influencing both developing and developed countries. Therefore, their rapid and accurate detection is of much concern in food safety and point-of-care diagnostics. In this study, a surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) for simultaneous detection of them was developed. Under optimal conditions, the proposed assay showed good linear responses in the ranges of 10 2 –10 7 cfu/mL and 10 2 –10 7 cfu/mL with limits of detection of 75 cfu/mL and 75 cfu/mL, respectively, for L. monocytogenes and S. typhimurium , respectively. The practicality of the LFA in real food sample (milk) was also validated. Overall, the proposed assay is promising and has a good chance to be employed for multiple pathogen detection in food products.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2018
·
IF 3.927
Chun-Er Lin,Li-Feng Fang,Shi-Yuan Du,Zhi-Kan Yao,Bao-Ku Zhu
A novel positively charged nanofiltration membrane was designed and prepared by a simultaneous cross-linking/quaternization of poly( m -phenylene isophthalamide)/polyethyleneimine (PMIA/PEI) blend precursor membrane. To improve the PEI retention ratio during precursor membrane fabrication, propanetriol glycidyl ether (PTGE) was used as a cross-linker. For nanofiltration preparation, the cross-linking time and p -xylylene dichloride (XDC) concentration were optimized. A comprehensive characterization of the nanofiltration membrane was conducted in terms of chemical composition, surface morphology, surface charge, pore structures and separation properties. Results indicated that the density of the positive charge increased after the simultaneous cross-linking/quaternization. The nanofiltration membrane with pore size in the range of 0.5–2 nm exhibited high MgCl 2 rejection of 94.4% and water permeability of 37.3 L m −2 h −1 at 0.4 MPa. Furthermore, to make a comparison between the PMIA/PEI nanofiltration membrane and the other PEI based nanofiltration membranes in the previous studies, an empirical upper bound correlation between water permeability and water/salt selectivity was established. Due to the high density of positive charge on the membrane, the mono-/divalent ion (Na + /Mg 2+ ) selectivity of this novel nanofiltration membrane was at a high level compared with recent reports and much higher than commercial nanofiltration membranes. This work provides an effective method for fabricating the highly positively charged nanofiltration membrane which has great potential for multivalent cations separation.
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MICROCHEMICAL JOURNAL
·
2018
·
IF 2.746
Zheng-Meng Jiang,Lan-Jin Wang,Zhao Gao,Bo Zhuang,Qiang Yin,E-Hu Liu
Deep eutectic solvents (DESs) have attracted increasing attention as eco-friendly and efficient alternatives to conventional organic solvents. In this study, five herbal medicines (HMs) including Caulis sinomenii , Coptis chinensis , Stephania tetrandra , Tetradium ruticarpum , and Sophora flavescens were selected for the first time to comprehensively evaluate the potential and effectiveness of DESs on the extraction of Morphinane, Protoberberine, Bisbenzylisoquinoline, Indole and Quinolizidine alkaloids , respectively. A total of 75 types of binary or ternary DESs with different polarity, viscosity, pH, and solubilization abilities were tailored to screen a suitable DESs for extraction of morphinane alkaloids from Caulis sinomenii , and the extraction conditions were optimized using response surface methodology (RSM) and artificial neural network hybridized with genetic algorithm (ANN-GA) for the first time. The results demonstrated that DESs were excellent solvents for extraction of alkaloids with superior efficiency to conventional extraction solvents. Moreover, both ANOVA and sensitivity analysis demonstrated that the most critical parameter for alkaloids extraction was water content in DESs. This study reveals the potential of eco-friendly DESs for applications involving the efficient extraction of bioactive alkaloids from natural sources.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 4
·3144-3155
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IF 2.993
Qu Fei,Li Xiaonan,Lv Xiaoxia,You Jinmao,Han Wenli
Photoinduced electron transfer (PET) has been used as reporter in the field of photoluminescence sensors and switches, and intermolecular PET is believed to be responsible for fluorescence quenching. Herein, the emissions of Tb-MOF can be quenched effectively by protamine based on PET. Compared with conventional electrostatic attraction mechanism, this approach suffers less interference from other charged substances and has a broader linear range of protamine from 3 to 5000 ng/mL with limit of detection (LOD) 1.21 ng/mL. Subsequently, the strong binding effect of protamine toward Hep ascribed to electrostatic attraction hinders the interaction between Tb-MOF and protamine, resulting in the high emissions of framework. The detection of Hep also shows a good linear range from 0.5 to 5 μM with LOD 0.27 μM. Finally, this novel probe is also successfully applied to the determination of protamine and Hep in human serum with satisfactory results.
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JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES
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2019
·
IF 0.987
Yang-Fang He,Han-Qing Cai,Hong-Mei Zhang,Zhi-Hui Ren,Huan Tang,Yan Li,Xiao-Wei Zhou,Wen-Long Liu,Jin Pei,Shu-Ying Liu
In order to understand the significant differences in activities and effects between Asian ginseng (ASG) and American ginseng (AMG), it is important to study the correlation between chemical structures and biological activities in the two types of herbs. However, more attention has been paid to the analysis of ginsenosides in previous reports distinguishing between ASG and AMG. There are some other bioactive compounds besides ginsenosides, however, few studies have focused on a systematic comparison of these types of compounds. Two metabolomic methods were developed in this study by qualitative data acquisition using normal phase liquid chromatography mass spectrometry (NPLC-MS) and reverse phase liquid chromatography mass spectrometry (RPLC-MS) respectively, in combination with principal component analysis (PCA). Results show that both NPLC-MS and RPLC-MS-based metabolomic methods are feasible in composition profiling, biomarker screening as well as in discrimination of ASG and AMG. 17 ginsenosides were identified as analytical markers in RPLC-MS-based metabolomic method. In comparison, using NPLC-MS-based method, 5 ginsonosides, two amino acids as well as 1 oligosaccharide were identified as analytical markers. Therefore, RPLC-MS-based metabolomic method exhibits better profiling in ginsenosides, while NPLC-MS-based metabolomic method offers the advantage that multiple active ingredients can be determined simultaneously. The two methods are both helpful in identification of biomarker as well as in discrimination of American ginsengs from Asian ginsengs.
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