MICROCHIMICA ACTA
·
2015
·Vol. 183
·期 1
·441-448
·
IF 3.741
Cao Gen-Xia,Wu Xiu-Ming,Dong Yu-Ming,Li Zai-Jun,Wang Guang-Li
We describe a colorimetric assay for the quantitation of melamine (MA). It relies on the observation that MA reverses the inhibition of the light-triggered activity of horseradish peroxidase (HRP) functionalized gold nanoclusters (HRP-Au NCs) by Hg(II) ions. The HRP-Au NCs catalyze the oxidation of the substrate 3,3’,5,5’-tetramethylbenzidine (TMB) by dissolved oxygen if exposed to visible light provided by a 300 W Xe lamp (λ ≥ 400 nm). The addition of Hg(II) suppresses the enzymatic activity due to the metallophilic interaction between Hg(II) and Au(I) present on the surface of the HRP-Au NCs. MA with its triazole ring can restore the catalytic activity of the HRP-Au NCs by inhibiting the metallophilic interaction. As a result of these findings, a colorimetric “turn-on” assay for MA was worked out that can be used to determine MA in the 0.2 to 15 μmol·L −1 concentration range and with a 72 nmol·L −1 detection limit, which is much lower than the established safety limit. The method was successfully applied to the quantitation of MA in (spiked) raw milk and milk powder, with recoveries ranging from 98.5 % to 101.5 %.
We describe a colorimetric assay for the quantitation of melamine (MA). It relies on the observation that MA reverses the inhibition of the light-triggered activity of horseradish peroxidase (HRP) functionalized gold nanoclusters (HRP-Au NCs) by Hg(II) ions.
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高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2015
·Vol. 75
·期 1
·82-89
·
IF 1.532
Xiao Zuo-Yi,Huang Shu-Xian,Zhai Shang-Ru,Zhai Bin,Zhang Feng,An Qing-Da
Abstract A one-pot method was introduced to fabricate Ag–SiO 2 hollow composite spheres with developed porosity by employing monodisperse carboxylic-capped polystyrene (PS–COOH) spheres as a hard template. During the synthetic process, Ag + ions were immediately anchored on the surface of the PS–COOH spheres via electrostatic interaction and readily reduced by employing polymethylhydrosiloxane (PMHS) as a reducing agent. At the same time, silica oligomers derived from the hydrolysis of PMHS and TEOS were slowly deposited on the PS–COOH spheres to form solid silica shells. Subsequent decomposition of the PS–COOH spheres in air induced the formation of Ag–SiO 2 hollow spheres. The as-prepared products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N 2 absorption–desorption study. The results show that the well-designed composite spheres featured thin and spherical silica shell (~10 nm), large surface area (>240 m 2 g −1 ) and mesopore (6.0–9.0 nm). In addition, the Ag–SiO 2 hollow composite spheres exhibited high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Graphical Abstract A one-pot method was reported to prepare Ag–SiO 2 hollow spheres with well-developed porosity, which exhibited high catalytic performance and durable activity for the reaction of 4-NP to 4-AP.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2014
·Vol. 16
·期 12
·1-11
·
IF 2.278
Wang Yun,Wang Feihu,Guo Yuan,Chen Rongjun,Shen Yuanyuan,Guo Aijie,Liu Jieying,Zhang Xiao,Zhou Dejian,Guo Shengrong
This paper reports the synthesis of monodisperse gold nanorods (GNRs) via a simple seeded growth approach in the presence of different aromatic additives, such as 7-bromo-3-hydroxy-2-naphthoic acid (7-BrHNA), 3-hydroxy-2-naphthoic acid (HNA), 5-bromosalicylic acid (5-BrSA), salicylic acid (SA), or phenol (PhOH). Effects of the aromatic additives and hydrochloric acid (HCl) on the structure and optical properties of the synthesized GNRs were investigated. The longitudinal surface plasmon resonance (LSPR) peak wavelength of the resulting GNRs was found to be dependent on the aromatic additive in the following sequence: 5-BrSA (778 nm) > 7-BrHNA (706 nm) > SA (688 nm) > HNA (676 nm) > PhOH (638 nm) without the addition of HCl, but this was changed to 7-BrHNA (920 nm) > SA (890 nm) > HNA (872 nm) > PhOH (858 nm) > 5-BrSA (816 nm) or 7-BrHNA (1,005 nm) > PhOH (995 nm) > SA (990 nm) > HNA (980 nm) > 5-BrSA (815 nm) with the addition of HCl or HNO 3 , respectively. The LSPR peak wavelength was increased with the increasing concentration of 7-BrHNA without HCl addition; however, there was a maximum LSPR peak wavelength when HCl was added. Interestingly, the LSPR peak wavelength was also increased with the amount of HCl added. The results presented here thus established a simple approach to synthesize monodisperse GNRs of different LSPR wavelengths.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 49
·期 16
·5772-5781
·
IF 2.305
Shi Junjun,Zhou Yuming,Zhang Yiwei,Zhou Shijian,Zhang Zewu,Kong Jie,Guo Mingpeng
Magnesium (Mg)-modified mesoporous alumina with different type and content of Mg was prepared and then used as the support for platinum-tin catalyst in propane dehydrogenation. It was found that the property of Mg in Al 2 O 3 varied with the way of the addition of Mg precursors. For the grafted Mg species, the connection between Al 2 O 3 and Mg was increased by the forming of Mg–O–Al bonds in the inner surface of Al 2 O 3 pore. While for the traditional impregnation, Mg was attached loosely to the outer Al 2 O 3 surface by the aggregation of MgO. Moreover, modifying the internal framework of Al 2 O 3 by suitable content of Mg can enhance the interaction between Sn and support, leading to more amounts of tin in their oxidized states, which was beneficial to enhance the interaction of Pt with SnO x species. As a result, agglomerations of metallic particles were suppressed and the catalyst exhibited the best catalytic performance in terms of activity and stability.
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高影响因子
FIBERS AND POLYMERS
·
2014
·Vol. 15
·期 10
·2118-2123
·
IF 1.113
Zhuang Guangqing,Zhang Yun,Jia Yanrong,Qi Dongming,Fan Qinguo,Shao Jianzhong
The monodispersed SiO 2 particles with perfect sphericity and desired particle sizes were synthesized by an improved Stöber method. The particle sizes and size distribution of colloidal silica could be regulated by adjusting reaction temperature, reaction time, and the concentrations of NH 4 OH, H 2 O and TEOS. Dynamic light scattering particle size analysis and SEM analysis confirmed a narrowly distributed particle size and good sphericity of the synthesized SiO 2 nanoparticles. The structural colors of silica/polyethyleneimine (SiO 2 /PEI) thin film fabricated on polyester fabrics were governed by SiO 2 particle size, assembly cycles and viewing angles, and the origin mechanism of the structural colors was based on the thin film interference theory. The resultant polyester fabrics showed vivid structural colors changing with the change in viewing angles, displaying a biomimetic variable coloration effect on textiles.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 50
·期 4
·1594-1604
·
IF 2.305
Zhu Yingming,Xu Dandan,Meng Ming
A series of Bi 2 S 3 /(BiO) 2 CO 3 composite photocatalysts with different loadings of amorphous Bi 2 S 3 were successfully synthesized through an ultrasonic-assisted ion-exchange reaction between thioacetamide (CH 3 CSNH 2 ) and (BiO) 2 CO 3 , and characterized by XRD, XPS, BET, EELS, EDX, SEM, TEM/HRTEM, UV–Vis, and photoluminescence (PL) techniques. The results of TEM/HRTEM, EELS, and EDX indicate that the composite catalyst Bi 2 S 3 /(BiO) 2 CO 3 has been successfully synthesized with the deposited Bi 2 S 3 present in amorphous state on the surface of (BiO) 2 CO 3 . The activities of the catalysts for RhB degradation under visible light show that the catalyst prepared under ultrasonic is more active than the one synthesized without ultrasonic. The optimized sample Bi 2 S 3 /(BiO) 2 CO 3 (U5.0) exhibits a much higher activity, about 4.8 times to that of pure (BiO) 2 CO 3 . Based upon the band structures of Bi 2 S 3 /(BiO) 2 CO 3 , it is deduced that the migration of the visible light-induced electrons from the conduction band of Bi 2 S 3 to that of (BiO) 2 CO 3 should have facilitated the separation of photogenerated carriers, as confirmed by the suppressed photoluminescence spectra. Using different scavengers, the ·O 2
− and holes are clearly identified as the main oxidative species for RhB photodegradation. In light of these observations, a potential photocatalytic mechanism of RhB degradation over Bi 2 S 3 /(BiO) 2 CO 3 is proposed.
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高影响因子
BMC Veterinary Research
·
2014
·Vol. 10
·期 1
·1-9
·
IF 1.743
Xiong Wen,Chen Yun,Wang Yu,Liu Jiaguo
Background Duck viral hepatitis (DVH) is an acute disease of young ducklings with few convenient and effective veterinary drugs to treat. In pathology, present study mainly focused on the immune mechanism, but very few studies have concerned with the role of oxidative stress in the pathogenesis of DVH. To study the antioxidative and hepatoprotective effects of icariin and its phosphorylated derivative against DVH, we prepared phosphorylated icariin (p-icariin) using the sodium trimetaphosphate–sodium tripolyphosphate method. Ducklings were drunk with icariin and p-icariin after being challenged with duck hepatitis virus 1 (DHV-1). We recorded the number of dead ducklings, gross pathological changes in the liver, and changes in indices of oxidative stress and liver injury. The correlations between these indices were also analyzed.Results Exposure to DHV-1 induced significant oxidative damage in ducklings. Administration of icariin or p-icariin attenuated liver pathological injury and significantly increased the survival rate, with better outcomes in ducklings treated with p-icariin than in those treated with icariin. Icariin and p-icariin also attenuated the changes in oxidative stress and liver injury. We found positive correlations among indices of oxidative stress (malondialdehyde and inducible nitric oxide synthase) and liver injury (alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase), suggesting that DHV-1 causes significant oxidative damage, which is related to the extent of hepatic injury.Conclusion sIcariin and p-icariin improved the survival and attenuated oxidative stress and liver dysfunction induced by DHV-1. These outcomes were better in ducklings treated with p-icariin than in those treated by icariin. The clinical effects of both components were related to their antioxidant activities.
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PubMed
高影响因子
IRANIAN POLYMER JOURNAL
·
2013
·Vol. 23
·期 1
·47-52
·
IF 1.053
Gan Linhuo,Zhou Mingsong,Yang Dongjie,Qiu Xueqing
Carboxymethylated lignin (CML), a water-soluble lignin derivative with more carboxylic groups introduced by chemical modification, can be used as dispersant in industry. In this paper, using the methods of zeta potential measurement, X-ray photoelectron spectroscopy and UV spectroscopy, natural graphite (NG) and high-purity graphite (HPG) were selected to investigate the adsorption characteristics of CML at the hydrophobic solid/water interface. The adsorption isotherm of CML on HPG was more suitable for the Langmuir model than the Freundlich model, whereas the opposite result was obtained for the adsorption of CML on NG. Moreover, the amounts adsorbed of CML on HPG increased with higher ionic strength and lowering solution pH. However, the uptake of CML on NG increased dramatically with adding NaCl under acidic condition, while the ionic strength had no obvious influence on the adsorption under neutral condition. With increasing solution pH, the amounts of CML adsorbed on NG were dropped under acidic condition followed by increases under alkaline condition. It is suggested that the interactions between CML and the minor metallic impurities on NG surface probably contribute considerably to the differences between adsorption behaviors of CML on NG and HPG in varying solution conditions. Moreover, the results showed that the adsorption mechanism of CML at graphite/water interface could be described by Lennard-Jones potential.
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高影响因子
CHROMATOGRAPHIA
·
2013
·Vol. 76
·期 23
·1569-1576
·
IF 1.437
Cheng Xiao-Dong,Peng Xi-Tian,Yu Qiong-Wei,Yuan Bi-Feng,Feng Yu-Qi
A new stationary phase which contains both negatively charged phosphate groups and positively charged amino groups was successfully synthesized by modification of amino-functionalized silica particles with trichlorophosphine oxide (POCl 3 ) for hydrophilic interaction chromatography (HILIC). The composition of the surface grafts was determined by Fourier transform infrared spectroscopy and elemental analysis. Various parameters, such as column temperature, water content, pH values and ionic strength of the mobile phase were investigated to study the retention mechanism. The results demonstrated that the stationary phase involved a complex retention process including surface adsorption, partitioning and electrostatic interactions. Under optimized conditions, the separation of nucleobases and nucleosides, water-soluble vitamins, organic acids on the novel stationary phase could be achieved in the HILIC mode.
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高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2013
·Vol. 68
·期 1
·54-59
·
IF 1.66
Li Jie,Chen LianXi,Li Xi,Zhang ZhongMing,Jiao CaiBin
A new class of poly(vinyl acetate) (PVAc)/silica nanocomposite particles was successfully prepared in aqueous solution through a facile synthetic process. First, vinyl functionalized silica nanoparticles (VFSs) were synthesized using one-step method in aqueous emulsion, and then the vinyl groups located on the surface of VFSs were used to induced in situ polymerization of vinyl acetate. Scanning electron microscopy (SEM) images showed that VFSs and PVAc/silica nanocomposite particles all revealed highly monodispersed and uniform spheres. Especially, PVAc/silica nanocomposite particles obtained from transmission electron microscopy images presented an obvious core–shell structure, and the thickness of PVAc shell grafting on the surface of VFSs core was about 17 nm. In addition, the influence of the hydrolyzed and condensed time of vinyl triethoxysilane on the size and size distribution of VFSs was also investigated. The results of dynamic light scattering and SEM analysis indicated that the size and size distribution of VFSs decreased gradually with the extension of the reaction time from 6 to 48 h. Moreover, the structures and thermal properties of the samples were characterized via FT-IR and heat-flow DSC–TG.
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高影响因子
POLYMER BULLETIN
·
2015
·Vol. 72
·期 10
·2455-2469
·
IF 1.438
Bai Liangjiu,Wang Dongju,Chen Hou,Li Dongxin,Xu Yuanyuan,Yu Lili,Wang Wenxiang
Abstract Peanut shell (PNS) was used to prepare a novel adsorbent to achieve resource recovery of the agricultural residue. The hydroxyl groups of peanut shell were turned into –C(CH 3 ) 2 –Br pendant groups to initiate polymerization of acrylonitrile. Graft copolymer peanut shell/polyacrylonitrile (PNS- g -PAN) was modified by hydroxylamine hydrochloride to transform the cyano groups into amidoxime (AO) groups. The modified copolymer of AO-PNS- g -PAN was used as adsorbent. The maximum adsorption capacity for Hg(II) was 4.45 mmol g −1 . The adsorption process fitted well the Freundlich isotherm model and followed pseudo-second-order model. The modified copolymer demonstrated its potential as an efficient adsorbent to solve the problem of Hg(II) contamination. Graphical abstract The peanut shell (PNS) macroinitiator was obtained by acylation of hydroxyl groups on the cellulose backbone of the peanut shell and initiated by Cu(0)-mediated RDRP of acrylonitrile. PNS- g -PAN was modified by NH 2 OH·HCl and used to remove heavy metal ions. The maximum adsorption capacity of Hg(II) was 4.45 mmol g −1 .
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高影响因子
MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 11
·1949-1956
·
IF 3.741
Wang Fang,Gong Wencheng,Wang Lili,Chen Zilin
Reduced graphene oxide (RGO) was used to construct a bienzyme biosensor containing horseradish peroxidase (HRP) and glucose oxidase (GOx). A poly(toluidine blue) (pTB) film containing RGO acted as both enzyme immobilization matrix and electron transfer mediator. The bienzyme biosensor was characterized by electrochemical techniques and displays a highly sensitive amperometric response to glucose and hydrogen peroxide (H 2 O 2 ) at a potential as low as −0.1 V (vs. SCE). It is shown that use of RGO causes a strong enhancement on the amperometric responses. H 2 O 2 formed by the action of GOx in the presence of oxygen can be further reduced by HRP in the pTB film contacting the RGO modified electrode. In the absence of oxygen, glucose oxidation proceeds by another mechanism in which electron transfer occurs from GOx to the electrode and with pTB acting as the mediator. Amperometric responses to glucose and H 2 O 2 follow Michaelis-Menten kinetics. The experimental conditions were optimized, and under these conditions glucose can be determined in the 80 μM to 3.0 mM range with a detection limit of 50 μM. H 2 O 2 , in turn, can be quantified in up to 30.0 μM concentration with a detection limit of 0.2 μM. The bienzyme biosensor is reproducible, repeatable and stable. Finally, it has been successfully applied to the determination of glucose in plasma samples.
Schematic representation of glocuse detection at GCE/RGO/pTB-HRP-GOx.
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高影响因子
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