ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 30
·7063-7075
·
IF 3.431
Wang Meng,Jiao Yang,Cheng Chunsheng,Hua Jianhao,Yang Yaling
A novel and sensitive method based on nitrogen-doped carbon quantum dots as a fluorescence probe coupled with magnetic solid-phase extraction (MSPE) purification for analysis of folic acid (FA) in human serum samples has been established for the first time. In the developed system, magnetic nanoparticles coated with hexanoic acid (Fe 3 O 4 @C 6 ) were synthesized by a one-step chemical co-precipitation method with good magnetic properties and dispersibility for sample purification, and it is better to be separated from the sample. High fluorescence nitrogen-doped carbon quantum dots (N-CQDs), simply prepared using a one-step hydrothermal method with nitrilotriacetic acid, could be selectively quenched by FA. Based on this phenomenon, a fluorescence assay was proposed for specific determination of FA. Various operational experiment parameters have been studied and optimized in detail. Under the optimum experimental conditions, the detection limit of the proposed method for FA was evaluated to be 0.5 nM (S/ N = 3), while the relative standard deviation (RSD) was 1.2% ( n = 6). Finally, the proposed method was applied for determination of trace levels of FA from human serum samples and quantitative recoveries were achieved within the range of 95.7–103.5%. All of the results showed that the proposed method had significant application in further research.
Schematic of synthesis of N-CQDs and schematic of suggested mode for analysis of folic acid (FA).
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 24
·期 30
·23538-23548
·
IF 2.741
Tang Fenglin,Xin Jia,Zheng Xilai,Zheng Tianyuan,Yuan Xianzheng,Kolditz Olaf
A microscale zero-valent iron (mZVI)-based in situ reactive zone is a promising technology for contaminated groundwater remediation. Estimation of mZVI aging behavior after its injection into the subsurface is essential for efficiency and longevity assessments. In this study, batch tests were conducted to investigate the effect of initial pH on mZVI aging dynamics, as well as the formation and evolution of aging products over 112 days. Results indicated that mZVI aging accelerated with decreasing initial pH. Corrosion rates of mZVI particles under pH 6.0 and 7.5 were approximately two orders of magnitude higher than those observed at pH 9.0. The morphological, structural, and compositional evolution of mZVI particles in three systems (pH = 6.0, 7.5, and 9.0) were investigated using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. In acidic and neutral solutions, a thick passivation layer with loosely and unevenly distributed aging precipitates was observed, and Fe 3 O 4 was the final aging precipitate. Nevertheless, in alkaline solutions, minute aging precipitates were detected on the mZVI surface at 112 day. Characterization results suggested that mZVI was oxidized via the Fe 0 –Fe(OH) 2 –Fe 3 O 4 route. These findings shed new light on mZVI aging mechanisms, particularly its physicochemical characteristics and the structural evolution of mZVI in field-scale groundwater remediation applications.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 1
·55-62
·
IF 1.624
Ren Hongbo,Zhu Jiayi,Bi Yutie,Xu Yewei,Zhang Lin
Humidity-resistant antireflective (AR) porous films with ultralow refractive indices were prepared via an one-step sol–gel process by assembly of methylated hollow silica nanospheres (HSNs). The hydrophobicity and refractive indices of silica-based AR porous films could be varied between 66.0° and 115.0°, and between 1.08 and 1.14, respectively, by tuning the MTES/TEOS molar ratios. A possible assembly mechanism was proposed according to the microstructure of methylated HSNs and porous films. The various properties of silica-based AR porous films were investigated and the AR porous film could demonstrate a good AR capability of 97.6% and excellent humidity resistance.
✓ 已验证
产品关联
DOI
高影响因子
Science China-Chemistry
·
2017
·Vol. 60
·期 10
·1367-1376
·
IF 4.132
Liu Yucheng,Ren Xiaodong,Zhang Jing,Yang Zhou,Yang Dong,Yu Fengyang,Sun Jiankun,Zhao Changming,Yao Zhun,Wang Bo,Wei Qingbo,Xiao Fengwei,Fan Haibo,Deng Hao,Deng Liangping,Liu Shengzhong Frank
As the large single-crystalline silicon wafers have revolutionized many industries including electronics and solar cells, it is envisioned that the availability of large single-crystalline perovskite crystals and wafers will revolutionize its broad applications in photovoltaics, optoelectronics, lasers, photodetectors, light emitting diodes (LEDs), etc. Here we report a method to grow large single-crystalline perovskites including single-halide crystals: CH 3 NH 3 PbX 3 (X=I, Br, Cl), and dual-halide ones: CH 3 NH 3 Pb(Cl
x
Br 1− x ) 3 and CH 3 NH 3 Pb(Br
x
I 1− x ) 3 , with the largest crystal being 120 mm in length. Meanwhile, we have advanced a process to slice the large perovskite crystals into thin wafers. It is found that the wafers exhibit remarkable features: (1) its trap-state density is a million times smaller than that in the microcrystalline perovskite thin films (MPTF); (2) its carrier mobility is 410 times higher than its most popular organic counterpart P3HT; (3) its optical absorption is expanded to as high as 910 nm comparing to 797 nm for the MPTF; (4) while MPTF decomposes at 150 °C, the wafer is stable at high temperature up to 270 °C; (5) when exposed to high humidity (75% RH), MPTF decomposes in 5 h while the wafer shows no change for overnight; (6) its photocurrent response is 250 times higher than its MPTF counterpart. A few electronic devices have been fabricated using the crystalline wafers. Among them, the Hall test gives low carrier concentration with high mobility. The trap-state density is measured much lower than common semiconductors. Moreover, the large SC-wafer is found particularly useful for mass production of integrated circuits. By adjusting the halide composition, both the optical absorption and the light emission can be fine-tuned across the entire visible spectrum from 400 nm to 800 nm. It is envisioned that a range of visible lasers and LEDs may be developed using the dual-halide perovskites. With fewer trap states, high mobility, broader absorption, and humidity resistance, it is expected that solar cells with high stable efficiency maybe attainable using the crystalline wafers.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 20
·12524-12539
·
IF 2.599
Hu Jin,Zhang Xinya
The expansion of the industrial needs of isocyanurate type polyisocyanates and the increasing pressure on reducing free toluene diisocyanate (TDI) monomer content necessitate a highly selective catalyst to ensure a lower free monomer content in the product. A catalyst screening was performed in terms of catalytic activity and catalytic selectivity. Of all the common trimerization catalysts, oligomeric Mannich base (OMB), as a special type of Mannich base catalysts, was synthesized and proved to have the most enhanced selectivity and enough activity for the oligomerization of TDI. The influence of temperature and catalyst concentration on its catalytic reaction was investigated by comparing their reaction rate and reaction selectivity. Dodecanol as a compatibility modifying agent was found to be a co-catalyst of OMB, with a synergistic effect on both the reaction rate and reaction selectivity. The oligomerization process was followed and investigated by gel permeation chromatography (GPC) and isocyanate (NCO) back-titration.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 17
·4139-4147
·
IF 3.431
Luo Yiheng,Dou Wenchao,Zhao Guangying
In this article, a facile and sensitive electrochemical method for quantification of Salmonella Pullorum and Salmonella Gallinarum ( S. Pullorum and S. Gallinarum) was established by monitoring glucose consumption with a personal glucose meter (PGM). Antibody-functionalized magnetic nanoparticles (IgG-MNPs) were used to capture and enrich S. Pullorum and S. Gallinarum, and IgG-MNPs- S. Pullorum and IgG-MNPs- S. Gallinarum complexes were magnetically separated from a sample using a permanent magnet. The trace tag was prepared by loading polyclonal antibodies and high-content glucose oxidase on amino-functionalized silica nanoparticles (IgG-SiNPs-GOx). With a sandwich-type immunoassay format, IgG-SiNPs-GOx were added into the above mixture solution and conjugated to the complexes, forming sandwich composites IgG-MNPs/ S. Pullorum and S. Gallinarum/IgG-SiNPs-GOx. The above sandwich composites were dispersed in glucose solution. Before and after the hydrolysis of glucose, the concentration of glucose was measured using PGM. Under optimal conditions, a linear relationship between the decrease of glucose concentration and the logarithm of S. Pullorum and S. Gallinarum concentration was obtained in the concentration range from 1.27 × 10 2 to 1.27 × 10 5 CFU mL −1 , with a detection limit of 7.2 × 10 1 CFU mL −1 (S/ N = 3). This study provides a portable, low-cost, and quantitative analytical method for bacteria detection; thus, it has a great potential in the prevention of disease caused by S. Pullorum and S. Gallinarum in poultry.
A schematic illustration of the fabrication process of IgG-SiNPs-GOD nanomaterials ( A ) and IgG-MNPs ( B ) and experimental procedure of detection of S. Pullorum and S. Gallinarum using GOD-functionalized silica nanospheres as trace tags based on PGM ( C ).
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Advanced Ceramics
·
2016
·Vol. 5
·期 4
·298-307
·
IF 0.957
Shen Hongfang,Lu Youjun,Wang Yanmin,Pan Zhidong,Cao Guozhong,Yan Xianghui,Fang Guoli
SrTiO3 nanoparticle (NP) photocatalyst was synthesized with a facile and environmentalfriendly hydrothermal method using tetrabutyltitanate, strontium oxide, and ethanolamine as precursors at low temperature without alkali as mineralizer for the first time. The SrTiO 3 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and N 2 Brunauer–Emmett–Teller (BET) method. The SrTiO 3 catalyst synthesized at 120 °C (STO-120) exhibited the highest photocurrent intensity among the samples synthesized at different hydrothermal temperatures. The high photocatalytic performance of STO-120 was mainly attributed to the more homogeneous and minimum nanoparticle size, the highest surface area, and the maximum light absorption property among the four different samples. This work presented an applicable and facile method to fabricate a highly active and stable SrTiO 3 photocatalyst for organic pollutant degradation.
✓ 已验证
产品关联
DOI
高影响因子
BIOLOGICAL TRACE ELEMENT RESEARCH
·
2016
·Vol. 174
·期 1
·85-92
·
IF 1.798
Zhou Sihui,Zhang Caiying,Xiao Qingyang,Zhuang Yu,Gu Xiaolong,Yang Fan,Xing Chenghong,Hu Guoliang,Cao Huabin
Molybdenum (Mo) is an essential trace element for animals and human beings. However, the negative effects on rumen function and distribution of trace elements in tissues induced by excessive Mo have not been well understood. Therefore, the purpose of present study was to investigate the impact of Mo on rumen microbiota, distribution of trace elements in various organs, and hematological parameters of goats. A total of 36 goats were randomly distributed into three groups with equal number and low-Mo and high-Mo groups were orally administered ammonium molybdate at 15 and 45 mg · Mo · kg −1 · BW respectively, while the control group received corresponding quantitative deionized water. The results showed that the total number of ciliate and protozoa protein concentration decreased significantly ( P < 0.01) on days 25 and 50. Concentrations of ammonia nitrogen and bacterial protein were significantly higher ( P < 0.05) in low-Mo group, while they were lower ( P < 0.05) in high-Mo group than the control group on days 25 and 50. In addition, Mo accumulated in serum and all detected tissues. Copper (Cu) and zinc (Zn) contents significantly decreased ( P < 0.05) in hair and serum on days 25 and 50, while Cu contents increased ( P < 0.05) and the change of Zn contents were not obvious ( P > 0.05) in other tissues on days 25 and 50. Besides, there was no obvious variation in iron (Fe) contents during whole experiment period ( P > 0.05). Furthermore, excessive Mo content had no significant effect on red blood cell (RBC) counts and hemoglobin (HGB) concentration ( P > 0.05) on days 25 and 50, while white blood cell (WBC) counts increased significantly ( P < 0.05) on day 50. These results indicated that excessive Mo content could impact the balance of ruminal microorganisms and interfere with the absorption and distribution of Mo and Cu mainly.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOID AND POLYMER SCIENCE
·
2017
·Vol. 295
·期 12
·2383-2393
·
IF 1.723
Zhang Mengmeng,Si Xiaowei,Jiang Dehao,Yang Xinlin,Lu Yan,Shen Yinghua
Functional polymer microspheres with fluorescent carbazole unit and various functional groups, such as amide, pyridyl, and imidazole, were prepared by distillation precipitation copolymerization of divinylbenzene (DVB) as a crosslinker, N-vinylcarbazole (NVCz), together with acrylamide (AAm), 4-vinylpyridine (VPy), and 1-vinylimidazole ((VIM) as functional monomers in acetonitrile in the absence of any stabilizer. The resultant polymer microspheres were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, photoluminescent spectroscopy, inductively coupled plasma (ICP), and X-ray photoelectron microscopy (XPS). The functional polymer microspheres acted as a “turn-off” chemical sensor with excellent stability for determination of copper cation (Cu 2+ ) in methanol via the quenching effect of fluorescence after adsorption of Cu 2+ from the solution through the capture ability of functional groups, such as pyridyl, imidazole, and amide on the surface of polymer microspheres. A good linear relationship was set up between the photoluminescence intensity at the emission peak of 352 nm and the Cu 2+ concentrations ranging from 0 to 1.0 μM with the presence of pyridyl group as a ligand. The effects of the functional groups were investigated on the fluorescent response for the microspheres as chemical sensors.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2017
·Vol. 19
·期 8
·1-11
·
IF 2.02
Cheong Ling-Zhi,Wei Yayu,Wang Hongbin,Wang Zhiying,Su Xiurong,Shen Cai
Zeolitic imidazolate frameworks (ZIF) represent one of the metal organic frameworks (MOF) with high potential for enzyme immobilization due to their exceptional chemical and thermal stability, negligible cytotoxicity, and easy synthesis under mild biocompatible conditions. Amine-functionalized ZIF-8 (An-ZIF-8) are capable of forming multipoint attachment via hydrogen bonding with lipase which will immobilize and further enhance stabilization of lipase. In addition, increased hydrophilicity of An-ZIF-8 will increase partitioning of An-ZIF-8 immobilized lipase at the aqueous/organic interface which enable lipase to expose its active site and retain its catalytic activity at its highest. Present study reports the use of ZIF-8 and An-ZIF-8 nanoparticles as carrier for Burkholderia cepacia lipase (BCL), compares the ester hydrolysis and transesterification activities of immobilized lipase with those of free lipase, and evaluates the reusability and recovery rate of the immobilized lipase. An-ZIF-8 nanoparticles (average 130.42 ± 0.55 nm) were facilely synthesized via mixing ZIF-8 nanoparticles with ammonia hydroxide solution. Despite having similar characteristics of high crystallinity and forming cuboid-like particles, An-ZIF-8 demonstrated significantly ( P < 0.05) lower Brunauer-Emmett-Teller (BET) surface area and higher thermal stability than ZIF-8. BCL were successfully immobilized on ZIF-8 (BCL@ZIF-8) and An-ZIF-8 (BCL@An-ZIF-8) nanoparticles with an average lipase loading rate of ~ 8 mg/g MOF. The immobilized BCL demonstrated no significant differences in terms of esters hydrolysis and transesterification activities with those of free BCL. BCL@An-ZIF-8 demonstrated superior catalytic stability in comparison to BCL@ZIF-8 with retainment of more than 80% of its initial hydrolysis and transesterification activity for at least 10 repeated runs. In addition, more than 80% of the BCL@An-ZIF-8 can be easily recovered during each cycle of the reusability test through simple centrifugation.
✓ 已验证
产品关联
DOI
高影响因子
Food Analytical Methods
·
2017
·Vol. 10
·期 9
·2964-2973
·
IF 2.038
Tang Yiwei,Li Min,Gao Ziyuan,Liu Xiuying,Gao Xue,Ma Tao,Lu Xiaonan,Li Jianrong
A novel fluorescence probe was designed and synthesized to quantify ractopamine in foods using molecularly imprinted polymer (MIP) as a specific recognition element and YF 3 :Yb 3+ , Er 3+ upconversion nanoparticles (UCNPs) as a fluorescence signaling component. The developed UCNP@MIP probe was characterized using X-ray powder diffraction, scanning electron microscopy, and thermogravimetric analysis. The fluorescence of UCNP@MIP probe was quenched specifically by ractopamine, and good linear regression ranging from 1.66 × 10 −8 to 3.3 × 10 −7 mol/L was obtained with the limit of detection of 8.6 × 10 −10 mol/L. This method was further applied to determine ractopamine in water and pork samples. Recoveries between 76.61 and 88.97% were obtained with relative standard deviation ranging from 1.15 to 2.67% ( n = 3). This UCNP@MIP probe combined high selectivity of MIP and high sensitivity of upconversion fluorophore and showed potential to determine various food chemical hazards.
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·2031-2037
·
IF 4.831
Xu Guiyun,Liang Shaoping,Fan Jinshi,Sheng Ge,Luo Xiliang
Negatively charged carboxylated nanocrystalline cellulose (CNCC) and positively charged poly(diallyldimethyl ammonium chloride) (PDDA) were alternatingly assembled on the surface of a glassy carbon electrode to form a relatively uniform polyelectrolyte multilayer nanocomposite (CNCC/PDDA) n . It was then incorporated into a matrix of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) electrodeposited on the surface of the electrode. The nanocomposites were prepared in various ratios of PEDOT and (CNCC/PDDA), and then characterized by transmission electron microscopy, scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. The PEDOT/(CNCC/PDDA) 4 nanocomposite showed the lowest electrochemical impedance and best electrocatalytic activity towards the oxidation of nitrite. Based on these findings, an amperometric sensor was developed which, if operated at 0.80 V (vs. SCE), can detect nitrite in the 0.2 μM to 1.73 mM concentration range with a 57 nM detection limit.
Carboxylated nanocrystalline cellulose (CNCC) and poly(diallyldimethyl ammonium chloride) (PDDA) were assembled to nanocomposite (CNCC/PDDA) n . Poly(3,4-ethylenedioxythiophene (PEDOT) was electrodeposited on the surface of (CNCC/PDDA) n and a sensitive amperometric sensor for detection of nitrite was developed based on PEDOT/(CNCC/PDDA) n .
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）