Food Analytical Methods
·
2018
·Vol. 12
·期 2
·517-525
·
IF 2.245
Li Weixia,Chen Ning,Huang Zhongping,Zeng Xiuqiong,Zhu Yan
Antibiotic residue has become a serious issue of food safety, due to the emergence of drug-resistant bacteria and their toxic side effects. Therefore, regarding the need, we herein report a rapid, sensitive, and selective switchable hydrophilicity dispersive solvent-based liquid-liquid microextraction (SHDS-LLME) method combined with high-performance liquid chromatography and UV detector for determining amphenicols in food products. In the off-line extraction procedure, the mixture of extraction solvent (butanol) and dispersive solvent (tetraethylenepentamine) was manually injected into the acidic aqueous sample solution. Specifically, after the fast neutralization reaction, the dispersive solvent was converted into water-soluble salt and phase separation was achieved. Under the optimal conditions, a good linearity was observed in the range of 0.27–50.0 μg kg −1 . The limit of detection for chloramphenicol (CAP) and thiamphenicol (TAP) were 0.03 and 0.08 μg kg −1 , respectively. Recoveries for the spiked samples obtained were between 81.5 and 113.5% and the relative standard deviation was less than 8.6%. The proposed method was successfully applied for the analysis of amphenicols in four food products.
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高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2019
·Vol. 29
·期 5
·1625-1636
·
IF 1.637
Zhang Rui,Zhu Xuyang,Liu Yi,Cai Youfeng,Han Qiong,Zhang Tongqing,Li Yu
In this work, the versatile filler (HNTs) consisted of a halloysite nanotube as skeleton and intermediate magnetic nanoparticles coating poly(dopamine + 3-aminopropyltriethoxysilane) derivate layer were prepared. PVDF membranes were then manufactured by incorporating a series of ratios of HNTs. The Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscope (TEM) results proved that the modified materials were successfully achieved. The morphologies of membranes were characterized by scanning electron microscope (SEM) and atom force microscope (AFM). Meanwhile the PVDF hybrid membranes exhibited a stronger hydrophilicity (contact angle is 53°), higher bovine serum albumin (BSA) rejection (99%) than pure membrane (87°and 54%), and hybrid membranes maintain a higher flux recovery rate (FRR) that attains 85.3% after two cycles. Besides, the composite membrane showed a good removal rate (97.2%) of methylene blue. According to above experimental parameters, the 6% (based on PVDF mass) HNTs composite membrane was defined as the experimental optimal selection, and it could provide a promising candidate for methylene blue solution separation.
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高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2012
·Vol. 296
·期 3
·1331-1340
·
IF 1.52
Chi Fangting,Wang Xiaolin,Xiong Jie,Hu Sheng
PVA functionalized with vinylphosphonic acid was prepared as a new adsorbent for uranyl (VI) adsorption from aqueous solutions. The vinylphosphonic acid was cografted onto PVA fibers by preirradiation grafting technique. The adsorbent were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The adsorbent was observed to possess a fibrous structure and was bonded with phosphonic acid groups successfully. The adsorbent was used for the adsorption of low levels uranyl (VI) ions from aqueous solutions. The influence of analytical parameters including pH, adsorption time, amount of adsorbent, metal ion concentration, and temperature were investigated on the recovery of uranyl (VI) ion in aqueous solution. The maximum adsorption capacity (32.1 mg g −1 ) and fast equilibrium time (30 min) were achieved at pH of 4.5 at room temperature. Thermodynamic parameters (Δ H ° = 2.695 kJ mol −1 ; Δ S ° = 31.15 J mol −1 K −1 ; Δ G ° = −6.748 kJ mol −1 ) show the adsorption of an exothermic process and spontaneous nature, respectively. The possible coordination mechanism was illustrated. Adsorption and desorption coexist in aqueous solutions and then the system becomes equilibrium.
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 39
·期 2
·211-218
·
IF 3.154
Wei Ren-Bo,Zhan Chen-Hao,Yang Yang,He Peng-Lin,Liu Xiao-Bo
With the expanding application of capacitors, thermal resistant dielectric materials are in high demand due to the increasing harsh environments where the capacitors are needed and the heat generated by the capacitors. Herein, we present polyarylene ether nitrile and titanium dioxide hybrids which can be used as thermal resistant dielectrics for these capacitors. Phthalonitrile modified titanium dioxide (TiO 2 -CN) and phthalonitrile end-capped polyarylene ether nitrile (PEN-Ph) are firstly prepared. After being cast into TiO 2 -CN/PEN nanocomposite films, these composites self-crosslink upon heating at 320 °C for 4 h, forming the polyarylene ether nitrile and titanium dioxide hybrids (TiO 2 -PEN). Improved dielectric constants which are stable from room temperature to 200 °C of these hybrids are observed, indicating the potential application of the hybrids as thermal resistant dielectrics.
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Scientific Reports
·
2018
·Vol. 8
·期 1
·1-12
·
IF 4.122
Yue Rui,Chen Qiumeng,Li Siqi,Zhang Xiaodan,Huang Yuming,Feng Ping
Here, we reported a novel one-step hydrothermal route for the facile synthesis of 1,6-hexanediamine functionalized magnetic chitosan microspheres (AF-MCTS), which were characterized by TEM, FT-IR and XPS to look into its morphology, surface functional groups, and adsorption mechanism of Cr(VI) from the aqueous solution. Cr(VI) adsorption on AF-MCTS as a function of contact time, Cr(VI) concentration, pH, and ionic strength was investigated. The adsorption process follows the Langmuir isotherm model and pseudo-second-order kinetic model. The AF-MCTS exhibited high performance for Cr(VI) removal with very fast adsorption rate (reaching equilibrium within 5 min) and high adsorption capacity (208.33 mg/g), which was 1.1 to 12 times that of other chitosan-based adsorbents. Cr(VI) adsorption onto AF-MCTS was an endothermic and spontaneous process. The recovery and reuse of AF-MCTS was demonstrated 11 times without obvious decrease in adsorption capacity. Mechanism study suggested that –OH rather than –NH 2 groups in AF-MCTS were the electron donors for reducing Cr(VI) to Cr 3+ . Consumption or addition of H + could trigger the reversible supramolecular coordination between Cr 3+ and chitosan. Given the easy preparation, low cost, and remarkable performance, AF-MCTS composite is expected to show promising potential for the practical application in removing toxic Cr(VI) from aqueous media.
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PubMed
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 91
·期 1
·82-91
·
IF 1.986
An Lin,Han Xin,Li Yaogang,Hou Chengyi,Wang Hongzhi,Zhang Qinghong
Abstract In recent years, tantalum oxynitride (TaON) semiconductor as one of the most efficient photocatalysts has been studied intensively owing to the appropriate potentials for overall solar water splitting. In this work, ZnS/CdS/γ-TaON composite photocatalysts with wide light response were successfully prepared by nitridation of Ta 2 O 5 at 800 °C in a wet NH 3 flowing and subsequently deposition CdS and ZnS quantum dots. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflection spectroscopy (DRS), N 2 adsorption–desorption isothermals, X-ray photoelectron spectroscopy (XPS), and so on. The photocatalytic property for hydrogen production was also studied. The results indicated that CdS and ZnS quantum dots with a diameter of 3–8 nm were uniformly dispersed on the surface of γ-TaON, which enlarged the spectral response of the ZnS/CdS/γ-TaON photocatalysts. And the optimized H 2 evolution rate of ZnS/CdS/γ-TaON composite (839.6 μmol h −1 g −1 ) is about 14 times higher than that of CdS/γ-TaON in the absence of any noble-metal cocatalyst and 47 times higher than that of Pt loaded γ-TaON sample. The enhanced photocatalytic activity is attributed to the higher separation efficiency of electrons and holes with the heterogeneous junction between ZnS, CdS, and γ-TaON. Besides, the presence of γ-TaON and ZnS also prevent the photocorrosion of CdS. The results provide a new insight for developing the TaON-based nanocomposite photocatalysts with enhanced stability and excellent photocatalytic H 2 production activity.
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CELLULOSE
·
2021
·Vol. 28
·期 10
·6513-6522
·
IF 5.044
Chen Siling,Li Jilong,Song Yiheng,Yang Quanling,Shi Zhuqun,Xiong Chuanxi
Flexible piezoelectric nanogenerators for energy harvesting are getting more and more attention nowadays by converting the mechanical energy to electric energy. Here, an environment-friendly piezoelectric nanogenerator based on the regenerated cellulose (RC)/MoS 2 nanosheet nanocomposite successfully exhibited a relative high output voltage of 2 V and current of 150 nA under slight press which were 5 and 7.5 times higher than those of the neat RC film, i.e. 0.4 V and 20 nA, respectively. In particular, the MoS 2 nanosheets were obtained through a simple, facile and low-cost pathway by mechanical exfoliation in triethanolamine. The nanocomposite film with MoS 2 nanosheets content of 4% exhibited a high piezoelectric constant ( d 33 ) of 19 pC/N, which was 6.3 times higher than that of the neat RC film ( i.e. 3 pC/N). Thus, the RC/MoS 2 piezoelectric nanogenerator has great potential applications in the fields of energy harvester, sensors and is of great significance to environment protection.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 41
·期 2
·288-296
·
IF 3.815
Tan Wan-Yi,Jian Ling-Feng,Chen Wei-Peng,Zhang Yong-Wen,Lu Xiao-Chuang,Huang Wan-Jun,Zhang Ji-Sheng,Wu Jing-Wu,Feng Jun-Li,Liu Yi-Dong,Cui Ting-Ting,Min Yong-Gang
Modified polyimides (MPIs) show great potential towards 5G communication applications, due to its excellent thermal stability, mechanical property and chemical stability as compared to most of polymers. Introducing fluoride groups or porous structure is favorable to ultra-low dielectric constant ( D k ) and dielectric loss ( D f ). However, the cost of the fluorinated MPIs is high and their synthetic processes are complicated, and porous MPIs suffer poor mechanical properties. Also, increasing the fraction of free volume is a very effective way to lower D k through introducing more ultra-low- D k air component. However, most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D f , hindering the application of MPIs in high-speed communication devices. Thus, it is highly desirable to develop intrinsic ultra-low- D k / D f MPIs at high frequency with less fluoric groups and nonporous structure. Herein, we introduce a facile and effective strategy to lower D k and D f through introducing rigid and large sterically hindered aromatic groups into MPIs. On the one hand, their large steric hindrance effect leads to low D k by increasing intrinsic free volume. On the other hand, the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D f by inhibiting dipole orientations. Based on this strategy, the spirobifluorene groups are preferred. The as-prepared MPIs show excellent dielectric performance with low D k of 2.74–2.76 and low D f of 0.00599 at 10 GHz, to some extent, exceeding the multiple fluorinated MPI with D k / D f of 2.67/0.00663 at 10 GHz.
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高影响因子
POLYMER BULLETIN
·
2016
·Vol. 74
·期 3
·625-639
·
IF 1.371
Zhang Jinglin,Liu Huidi,Liu Hongxi,Hu Jian,Tan Shaozao,Wu Ting
Abstract A composite anion exchange membrane of crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene (CQPECH/PTFE) had been prepared via a green and facile method, where diethylamine, 1-methylimidazole and PTFE, respectively, served as crosslinking agent, quaternization reagent and supporting material. The structure and morphology of CQPECH/PTFE membrane were investigated. Water uptake, swelling ratio, ionic exchange capacity, hydroxide conductivity, chemical stability, and thermal and mechanical properties were measured to evaluate its performance in a direct methanol alkaline fuel cell. The results indicated that CQPECH had penetrated into the pores of PTFE membrane, showing a dense and uniform structure without any pore and phase separation. Besides, CQPECH/PTFE membrane exhibited high ionic conductivity, considerable ionic exchange capacity, moderate water uptake and low swelling ratio. More importantly, the obtained composite membrane displayed high tensile strength and good chemical and thermal stability, suggesting the great potential application of CQPECH/PTFE membrane as anion exchange membrane. Graphical abstract Crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene composite anion exchange membrane had been prepared via a green and facile method, where diethylamine served as crosslinking agent. With a dense and uniform structure without any pore and phase separation, the obtained composite membrane exhibited high tensile strength and good chemical stability.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 51
·77344-77358
·
IF 5.19
Ding Baoting,Wang Xiaomeng,Feng Kun,Fu Jingran,Liang Jianru,Zhou Lixiang
Acidic Cr(VI)-containing wastewater has received increasing attention in recent years. Schwertmannite is a suitable adsorbent for its acid resistance and good adsorption ability. However, it shows poor Cr(VI) adsorption performance under acidic conditions. Herein, inspired by the fast neutralization-mineralization process of acid mine drainage (AMD) triggered by alkaline rocks, a novel nano-scaled schwertmannite (Sch-2.7) with high Cr(VI) adsorption capacity was synthesized at constant pH of 2.7 via adding OH − . Compared with common schwertmannite (Sch), appropriate OH − effectively improved mineral yield (the precipitation efficiency of Fe: 96.75% vs. 29.93%), specific surface area (65.1 m 2 /g vs. 18.9 m 2 /g), surface group content, and further Cr(VI) adsorption ability of Sch-2.7. The maximum adsorption capacity was 54.17 (pH = 3), 61.59 (pH = 4), and 66.5 mg/g (pH = 5) for Sch-2.7, whereas only 20.35, 24.51, and 27.17 mg/g for Sch. On average, the former was 2.53 times higher than the latter. Temperature and coexisting ions had little influences on the sorption process of Sch-2.7. The mechanism analysis demonstrated that the Cr(VI) removal by Sch-2.7 was a more thermodynamic favorable process due to abundant reactive-active components on Sch-2.7 for adsorption reaction. This work provided new insight into performance optimization and application potential on Cr(VI) removal of schwertmannite.
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PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2018
·Vol. 411
·期 3
·787-795
·
IF 3.307
Zhang Hua-Yin,Tan Xiao-Xin,Kang Kai,Wang Wei,Lian Kao-Qi,Kang Wei-Jun
Lactic acid and pyruvic acid are important metabolites in the tricarboxylic acid cycle that can reflect the cytoplasmic redox state and mitochondrial respiratory chain function. The combination of these acids is considered as a screening index for mitochondrial disorders. Due to their biological effects, a derivatization method was developed to simultaneously detect pyruvic acid and lactic acid in tissue and cell culture media using gas chromatography. In this work, the combined derivatization method with methoxyamine hydrochloride and isobutyl chloroformate was first proposed. To improve the efficiency of derivatization, in situ derivatization-ultrasound-assisted emulsification microextraction (USAEME) was used in this study. After optimizing the volume of reagents and reaction times, good linearity values were obtained from 50 to 1000 μmol/L and 1 to 100 μmol/L for lactic acid and pyruvic acid, respectively. The limits of detection (LODs) were 0.12 μmol/L for lactic acid and 0.29 μmol/L for pyruvic acid. The recoveries of the two analytes were between 93.60 and 102.80%, and the precisions were less than 6.20%. This method was successfully applied to quantify pyruvic acid and lactic acid in the animal and cellular hypoxia models which provided an auxiliary means for the diagnosis of mitochondrial diseases.
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高影响因子
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 25
·期 3
·237-244
·
IF 0
Xu Yan,Wang Fan,Hou Qingfeng,Zhao Yujun,Ding Guosheng,Xu Xingguang
In this study, we developed a strategy for using the Scoggins procedure in the synthesis of acetamidines as novel CO 2 -triggered switchable surfactants via acetimidates by effectively tuning the chemical equilibrium. The as-synthesized N ’-alkyl- N , N -diethylacetamidines exhibit excellent CO 2 /N 2 switchability and their bicarbonate salts have the ability to emulsify oil–water mixtures.
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危险品化学品经营许可证（带存储）