CHROMATOGRAPHIA
·
2015
·Vol. 78
·期 15
·979-985
·
IF 1.411
Li Gongheng,Zhang Xinfeng,Zhang Leilei,Xu Shuxia,Li Chongying
In this study, an efficient sample pretreatment method, salt-assisted graphene oxide dispersive solid phase microextraction (SA-GO-DSPME), was established for extraction of malachite green (MG) and crystal violet (CV). The dispersive graphene oxide was found to be easily aggregated and completely centrifuged in the presence of NaCl. The adsorption kinetic of SA-GO-DSPME was shown to be quite fast (equilibrium time = 5 min). Key parameters that influenced extraction efficiency including sample pH, the eluent type, GO amount, extraction time, NaCl concentration and centrifuging time were investigated. Coupled with SA-GO-DSPME, high-performance liquid chromatography (HPLC) could be used for sensitive detection of MG and CV with detection limits down to 1.7 and 0.3 ng mL −1 for MG and CV, respectively. The relative standard deviations for extraction reproducibility ( n = 5) were 1.8 % for MG and 3.8 % for CV. The proposed method has been successfully applied for detection of MG and CV in real water samples, and the recoveries ranged from 89.7 to 116.4 %. This simple and fast extraction method may provide a promising alternative for extraction of trace amount of MG and CV in complicated samples.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2015
·Vol. 50
·期 9
·3399-3408
·
IF 2.371
Gao Yongju,Zhao Songfang,Zhang Guoping,Deng Libo,Li Jinhui,Sun Rong,Li Liyi,Wong Ching-Ping
Hierarchically porous organosilica microspheres have been facilely synthesized by improved self-assembly of flexible-bridged organosilica precursor without templates and harsh conditions. Subsequently, monodispersed silver nanoparticles (Ag NPs) are in situ grown on the porous microspheres via silver mirror reaction.
The as-prepared hybrid composites of Ag supported on porous microspheres are characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis and nitrogen adsorption and desorption, respectively. These results indicate that not only Ag NPs (20–40 nm) are grown on the organosilica uniformly but also the content of Ag NPs immobilized in the hybrid materials can be well controlled by simply tuning the amount of the Ag(NH 3 ) 2 OH. The resultant hybrid microspheres exhibit remarkable and durable performances for the reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 in aqueous solution. Moreover, the catalytic kinetic mode can be tuned by adjusting the parameter in catalytic reaction, and it can be recycled for seven successive cycles with excellent conversion of 100 % within 8 min. Therefore, the present structure design and scalable route for the synthesis of hierarchical catalyst can provide a highly efficient solution for the reduction of nitro-aromatic compounds in the view of environmentally friendly strategy.
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高影响因子
ARCHIVES OF PHARMACAL RESEARCH
·
2015
·
IF 2.046
Zhang Fengsu,Cai Hao,Liu Xunhong,Chen Fei,Yang Nianyun,Hou Ya,Ma Yang,Luo Yiyuan,Liu Juanxiu
To analyze the components of the fatty oil extracted from Antrodia camphorata fungus powder and to evaluate the antioxidant activity of A. camphorata crude oil. A derivatized gas chromatography mass spectrometry (GC–MS) was developed for the quantification of 19 fatty acids in extracts of A. camphorata obtained by supercritical carbon dioxide (SC-CO 2 ). Good separation was obtained under the optimized chromatographic conditions and 19 target compounds after methyl-esterification were identified by GC–MS on a HP-VOC capillary column (60 m × 320 μm × 1.8 μm) with an initial temperature set at 80 °C. The validity of the established method was examined experimentally with good linearity, intra-assay precisions, repeatability, stability and recovery. The antioxidant activity of A. camphorata crude oil was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Nineteen fatty acids showed good linearity over the tested ranges (r > 0.9956) and the recovery ranged from 93.47 to 104.89 %. The crude oil extracted from A. camphorata fungus powder also revealed its antioxidant activity. It was the report about simultaneous determination of 19 fatty acids in A. camphorata and antioxidant activity of its crude oil for the first time. The established method might also be utilized for the investigation of edible plant materials and agricultural products containing fatty acids.
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PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2017
·Vol. 122
·期 1
·525-538
·
IF 1.264
Li Xin,Meng Fanhui,Cheng Yang,Gao Yuan,Li Zhong
Mesoporous silica (SiO 2 ) supported highly dispersed Ni catalysts with ZrO 2 and surfactant β-cyclodextrin (CD) were prepared by the impregnation method, and their catalytic performance for three-phase methanation of CO were evaluated. It is shown that ZrO 2 promotes the dispersion of Ni species on mesoporous SiO 2 , leading to the increase in Ni dispersion and methanation activity. For the ZrO 2 content, the optimum is 5 wt%. Moreover, when adding CD in the preparation of Ni5Zr/SiO 2 catalyst, CD was found effectively enhanced the dispersion of Ni species and interaction between Ni species and support, leading to a smaller size of NiO particles and more exposed active surfaces, which promotes the CO adsorption capacity. As the molar ratio of CD/Ni rises, the crystallite size of metallic Ni decreased. Ni5Zr/SiO 2 (1:5) catalyst prepared with 5 wt% ZrO 2 and 1:5 molar ratio of CD/Ni shows the optimal catalytic activity for the three-phase CO methanation reaction. This is because of the highest dispersion of metallic Ni and smallest size of NiO particles.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 9
·3171-3178
·
IF 4.58
Zhan Lei,Yang Tong,Zhen Shu Jun,Huang Cheng Zhi
This work reports on a colorimetric platform for determination of chromium ions (Cr 3+ ) and mercury ions (Hg 2+ ) using silver nanoparticles (AgNPs) capped with cytosine triphosphate (CTP). The capped AgNPs were synthesized one-step by reduction of AgNO 3 in the presence of CTP. It was found that such AgNPs aggregate in the presence of Cr 3+ . This results in a decrease in the intensity of the surface plasmon resonance (SPR) band at 390 nm and the formation of a new red-shifted band at 510 nm, and consequently a color change from yellow to red. Different from the Cr 3+ -induced aggregation of AgNPs, exposure to Hg 2+ causes the formation of a mercury layer around the surface of the AgNPs. This, in turn, causes the SPR absorption of the AgNPs to decrease and to undergo a slight blue shift, and this results in a fading of the yellow color. The findings are the basis of developing a new method for quantification of either Cr 3+ or Hg 2+ , with detection limits of 6.25 μM for Cr 3+ and of 0.125 μM for Hg 2+ , respectively. The method was applied to the determination of the two ions in spiked drinking water and lake water samples, and recoveries ranged from 94.5% to 101.3% for Cr 3+ , and from 96% to 108% for Hg 2+ , which is satisfactory for quantitative assays performed in water samples.
Cytosine triphosphate-capped silver nanoparticles (cAgNPs) are shown to represent a viable probe for visual and colorimetric detection of Hg 2+ and Cr 3+ via two different mechanisms: aggregation of cAgNPs in case of Cr 3+ ; and amalgamation of cAgNPs in case of Hg 2+ .
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IONICS
·
2017
·Vol. 23
·期 11
·3211-3218
·
IF 2.062
Xu Guiyun,Liang Shaoping,Zhang Mingming,Fan Jinshi,Feng Jiuju,Yu Xijuan
Carboxylated cellulose nanocrystals (CNCC) were synthesized by treating microcrystalline cellulose with ammonium persulfate. Silver nanoparticles (AgNPs) were prepared on the surface of CNCC using NaBH 4 as reductant. Novel conducting nanocomposites of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with AgNPs/CNCC were electrodeposited on the surface of the glassy carbon electrode. The nanocomposites prepared in various ratios of PEDOT, CNCC, and AgNPs were characterized by scanning electron microscopy, transmission electron microscope, electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. The prepared PEDOT/AgNPs/CNCC showed much low electrochemical impedance and very good response towards the oxidation of dopamine. Based on these findings, a highly stable, sensitive, and selective amperometric sensor for the detection of dopamine was developed. Operated at 0.20 V (vs. Ag/AgCl), the sensor can detect dopamine in the range of 0.05 to 782 μM with a 17-nM detection limit.
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APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2017
·Vol. 123
·期 6
·1-4
·
IF 1.455
Wen Xiaoyu,Pan Xiaona,Wu Libin,Li Ruinan,Wang Dan,Zhang Jinqiu,Yang Peixia
Lamellar tin deposits were prepared by galvanostatical electroplating from the aqueous acidic-sulfate bath, with gelatin and benzalacetone dissolved in ethanol (A BA+EtOH ) as additive, and their morphologies were investigated by scanning electron microscopy. Cathodic polarization curves revealed that the absorbability of A BA+EtOH on the cathode surface was higher than that of gelatin. X-ray diffraction analysis indicated preferred orientations of tin growth led to the formation of lamellar structure and distortion of tin lattice. The growth mechanism of lamellar tin was also discussed.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2017
·Vol. 28
·期 12
·9081-9090
·
IF 2.019
Wang Zhen,Ru Qiang,Mo Yudi,Guo Lingyun,Chen Xiaoqiu,Hou Xianhua,Hu Shejun
In this work, we develop an effective strategy to synthesize porous peanut-like ZnCo 2 O 4 (ZCO) decorated with graphene/Carbon nanotubes (CNTs) as an effective anode material for long cycling life lithium storage via a facile solvothermal process and rapid cold-quenching method. SEM and TEM characterizations show that graphene and CNTs serving as the elastic support and superior conductive network wrap the porous peanut-like ZCO, which can enhance electrochemical performance. The as-prepared ZnCo 2 O 4 /reduce graphene oxide/carbon nanotubes (ZCO/rGO/CNTs) delivers an initial discharge capacity of 1214.1 mAh g −1 at a current density of 500 mA g −1 and exhibits a high discharge capacity (1026.6 mAh g −1 after 200 cycles) when evaluated as anode materials of LIBs. More interestingly, the reversible capacity of the ZCO/rGO/CNTs even retains 728.6 mAh g −1 after 300 cycles even at a high current density of 1000 mA g −1 . The good cycling capability, high rate performance and reliable electrode adaptability suggest that the ZCO/rGO/CNTs will be an attractive material for lithium ion batteries.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 9
·3247-3253
·
IF 4.58
Wang Huiqiang,Ma Zhanfang
A glassy carbon electrode was modified with a redox-active nanocomposite consisting of polyresorcinol, gold nanoparticles (NPs) and platinum NPs. This nanocomposite possesses the following outstanding advantages: (1) strong electrochemical signal towards H 2 O 2 at 0.92 V (vs Ag/AgCl); (2) good conductivity; and (3) ease of immobilization of antibody without the use of coupling agents. Based on these properties, a label-free amperometric immunoassay for the tumor marker neuron-specific enolase (NSE) was developed. The immunoelectrode has a linear response in the 10 pg·mL −1 to 100 ng·mL −1 NSE concentration range and a 7.8 pg·mL −1 detection limit (at an SNR of 3). The method was applied to the quantitation of NSE in human serum samples and showed satisfactory accuracy compared to an electrochemiluminescence immunoassay, a commonly used method in clinical applications.
A novel multifunctional substrate was synthesized by a one-pot method using resorcinol as monomer, and HAuCl 4 and H 2 PtCl 6 as co-oxidizing agents. It was used to fabricate an ultrasensitive amperometric immunosensor for tumor biomarker.
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JOURNAL OF FLUORESCENCE
·
2017
·Vol. 27
·期 4
·1495-1503
·
IF 1.461
Lin Bixia,Yu Ying,Liu Fangfei,Cao Yujuan,Guo Manli
Indole propionic acid (IPA) is one of the important plant growth hormones for promoting rooting and fruiting. Labeling IPA receptor in plant tissues is able to further track the signal transduction processes of IPA and uncover the function mechanism of IPA on crop productions. In this paper, a tunable and nontoxic fluorescent probe for IPA receptors was designed and synthetized base on carbon dots (C dots). Firstly carboxyl-modified carbon dots were prepared by high temperature cracking of citric acid. The fluorescence emission wavelengths of C dots varied with the excitation wavelengths change. Then IPA-modified carbon dots (IPA-C dots) were prepared by coupling the amino of tryptophan with the carboxyl of as-prepared carbon dots. Compared with C dots, the fluorescence intensity of IPA-C dots was double and the fluorescence stability was satisfactory under various conditions. This probe retained the biological activity of IPA and acted as target recognition of IPA receptors in plant tissues. The probe could avoid green fluorescence background of plants. The imaging results showed that the IPA receptors mainly existed on the membrane of stele. The toxicity test indicated the probe was less toxic than traditional inorganic semiconductor quantum dots.
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PubMed
高影响因子
JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 1
·189-198
·
IF 1.624
Feng Zhouzhou,Lv Xiang,Wang Tianhe
TiO 2 porous ceramic/Ag–AgCl composite was prepared by incorporating AgCl nanoparticles within the bulk of TiO 2 porous ceramic followed by reducing Ag + in the AgCl particles to Ag 0 species under visible light irradiation. The porous TiO 2 ceramic was physically robust and chemically durable, and the porous structure facilitated the implantation of AgCl NPs. Compared with the bare TiO 2 ceramic, TiO 2 porous ceramic/Ag–AgCl composite exhibited higher photocatalytic performance for the degradation of MO and RhB under visible light irradiation. The reaction rate constants k of MO and RhB degradation over TiO 2 porous ceramic/Ag–AgCl composite was respectively 6.25 times and 3.62 times higher than those recorded over the bare TiO 2 porous ceramic. The photocatalytic activity showed virtually no decline after four times cyclic experiments under visible light irradiation. Scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectra and X-ray photoelectron spectroscopy were used to characterize the TiO 2 porous ceramic/Ag–AgCl composite.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 8
·2919-2924
·
IF 4.58
He Linghao,Guo Chuanpan,Song Yingpan,Zhang Shuai,Wang Minghua,Peng Donglai,Fang Shaoming,Zhang Zhihong,Liu Chun-Sen
The authors describe an electrochemical immunoassay for the β-adrenergic agonist ractopamine (RAC). It is based on the use of chitosan-stabilized gold nanoparticles (chit-AuNPs). Antibodies against RAC (anti-RAC) readily adsorb on the surface of the chit-AuNPs due to their high bio-affinity. The amount of chitosan used to synthesize chit-AuNPs does not affect the size and distribution of the NPs but amplifies the electrochemical signal of the electrode. The assay has a detection limit as low as 2.3 pg∙mL −1 (equivalent to a 6.7 fM concentration), with a response that is linear in the 0.01 to 5 ng∙mL −1 RAC concentration range. The assay is selective, acceptably reproducible, stable, and well applicable to the detection of RAC.
Chitosan-stabilized gold nanoparticles (chit-AuNPs) were prepared for electrochemical immunoassay of the ractopamine (RAC). The assay exhibits a detection limit of 2.3 pg·mL −1 (equal to 6.7 fM), is highly selective, acceptably reproducible, and stable.
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