Analytical Methods
·
2019
·Vol. 11
·期 48
·6176-6183
·
IF 2.378
Fei-Fei Li,Hui-Xiang Liu,Yan-Li Zhang,Shu-Qi Wang
Absorbable vascular sealing medical glue, which belongs to Class III medical devices, is a special new material for preventing the leakage of cerebrospinal fluid. Medical four-arm poly(ethylene glycol)-N-hydroxysuccinimide-glutarate (4-arm-PEG-SG) with a molecular weight of 20 000 is the main component of the absorbable medical glue. According to its quality standard, the quality control of residues 1,3-dicyclohexylurea (DCU), glutaric acid (GA) and triethylamine (TEA) is required. A rapid analytical method of quantitative 1H nuclear magnetic resonance (1H NMR) for the determination of residues DCU, GA and TEA in medical 4-arm-PEG-SG was established in the present study. The peaks at δ 1.56 (4H, m), δ 2.71 (4H, t, J = 6.7 Hz), and δ 2.42 (6H, q, J = 7.2 Hz) were selected for quantifying DCU, GA and TEA, respectively, with deuterated pyridine as the solvent and tetramethylsilane as the internal standard. The 1H NMR assay was validated by several experimental parameters including specificity, linearity, accuracy, precision, robustness, limit of detection (LOD), limit of quantification (LOQ) and stability. The average recoveries obtained were in the range of 99.48–102.02% for all three residues. Compared with the HPLC and GC approaches, the proposed 1H NMR method proved to be a powerful tool for quantification due to its unique advantages of simplicity, rapidity and high robustness, especially not requiring standard compounds for calibration curve preparation.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Haiyan Jin,Jiayi Chen,Shanjun Mao,Yong Wang
Tungsten carbide (WC) materials have exhibited platinum-like catalytic behavior in many fields, whereas the adsorption of pure tungsten carbide for H is too strong and demonstrates low activity for hydrogen evolution reaction (HER). Herein, we successfully introduced transition metal into WC lattice and optimized the electron structure around Fermi level (EF) of WC via facile annealing CoW-based metal–organic framework precursors. X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption fine structure verified the incorporation of Co and the contraction of WC lattice. Density functional theory calculations indicated that the doping of Co into WC significantly increases the state density of WC at EF derived from the delocalization of Co charge, resulting in the moderate H2O binding energy and weakened H adsorption. As expected, the optimal Co-doping WC (Co/W molar ratio = 3) efficiently catalyzed HER with a low onset potential (31 mV) and a current density of 10 mA cm–2 at a low overpotential of 98 mV in 1.0 M KOH media, which was superior to that of WC/CN and Co/CN. Similarly, Ni and Fe could also modulate the electronic structure of WC and improve the HER activity.
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高影响因子
Micro & Nano Letters
·
2018
·Vol. 13
·期 6
·804-806
·
IF 0.841
Cheng Ju,Xiang Gong,Wenhao Song,Yu Zhao,Ruijun Li
This work reported the fabrication of bovine serum albumin stabilised gold nanoclusters (BSA-Au NCs)–graphene oxide nanocomplex (BSA-Au NCs-GO) as a ‘turn-on’ fluorescent probe for the detection of Cd 2+ . The prepared BSA-Au NCs showed an intense red fluorescence, and the fluorescence of BSA-Au NCs was reduced significantly by graphene oxide due to its excellent quenching properties. However, in the presence of 65 µmol l −1 Cd 2+ , the fluorescence intensity recovered to 82.5% of the intensity of BSA-Au NCs, and the fluorescence intensity increased 1.3-fold relative to the BSA-Au NCs-GO nanocomplex. This proposed probe expands the application of BSA-Au NCs, which can be used as a reversible fluorescence nanoswitch for inexpensive, label free and simple detection of Cd 2+ in the aqueous samples.
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TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 25
·期 1
·52-65
·
IF 0
Li Wang,Zhang Qingjun,Zeng Aiwu
In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest (≈ 81 kJ mol −1 ), while that of benzyl alcohol oxidation to benzaldehyde was the lowest (≈ 57 kJ mol −1 ). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower (≈ 1.9 kJ mol −1 ) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism (Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed (Δ H ads,Oxy ≈ − 15 kJ mol −1 , Δ H ads,Bald ≈ − 30 kJ mol −1 ), but showed strong mobility (Δ S ads,Oxy ≈ − 22 J mol −1 K −1 ), Δ S ads,Bald ≈ − 39 J mol −1 K −1 ). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Jiajiang Lin,Mengqiang Sun,Binglin Su,Gary Owens,Zuliang Chen
While phytogenic nanomaterials have been successfully used to remove heavy metals in wastewater, the potential to successfully use such materials to immobilize heavy metals in soils is still unclear. In this study, phytogenic iron oxide nanoparticles (PION) were used to immobilize cadmium (Cd) in six soils. Amendment with PION effectively immobilized Cd, with a concomitant increase in the concentrations of iron oxides, soil pH and dissolved organic carbon (DOC) under both oxic and anoxic conditions . However, observed changes in soil properties and Cd fractions were different under oxic and anoxic conditions. After PION application, the exchangeable Cd fraction decreased by up to 91 and 69%, while the carbonate bound Cd fraction decreased by up to 61 and 75%, under oxic and anoxic conditions, respectively. Pearson correlation analysis revealed that under both oxic and anoxic conditions, Cd fractions were significantly and positively correlated with free iron oxide content and pH, where free iron oxide content was positively correlated with amorphous iron oxide, DOC and pH. The Cd immobilization mechanisms potentially involved either (1) formation of insoluble hydroxides at elevated pH; (2) participation of biomolecules released from PION in ligand complexation with Cd and (3) co-precipitated of Cd during the formation of iron oxides. This study provided new insights into the potential effects of PION applications for practical Cd immobilization in contaminated soils.
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JOURNAL OF CHEMICAL THERMODYNAMICS
·
2018
·
IF 2.631
Jing Fan,Qi Liu,Fenhong Song,Xiaopo Wang,Lihui Zhang
The utilization of biodiesel is a promising way to replace fossil fuels, and thermal conductivity of biodiesel is a very important thermophysical property for its applications. In this work, the transient hot-wire instrument with one bare platinum wire was used to measure the thermal conductivity of five pure components of biodiesel in liquid phase at atmospheric pressure. The measured substances include methyl butyrate, methyl pentanoate, methyl caproate, methyl caprylate, and methyl pelargonate, and the temperature range was from (283 to 358) K, (285 to 362) K, (263 to 368) K, (273 to 393) K, (278 to 383) K, respectively. The total standard uncertainty of the experimental results was estimated to be less than 2% and the repeatability was better than ±0.5%. The thermal conductivity data of each substance were fitted as a function of temperature. The average absolute relative deviation and maximum absolute relative deviation between the experimental data and calculated results were 0.17% and 0.44% for methyl butyrate, 0.25% and 0.58% for methyl pentanoate, 0.16% and 0.44% for methyl caproate, 0.15% and 0.47% for methyl caprylate, 0.15% and 0.33% for methyl pelargonate, respectively.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Fan Fang,Nengjie Feng,Lei Wang,Jie Meng,Geng Liu,Peng Zhao,Pengfei Gao,Jing Ding,Hui Wan,Guofeng Guan
Perovskite-type macro/mesoporous nanotube shows large specific surface area and high utilization of catalytic sites, which gives rise to the enhancement of catalytic activity and broaden their application. In this work, perovskite-type La 1-x K x FeO 3-δ nanotubes were prepared for efficient soot oxidation by a simple electrospinning technique following calcination. The as-prepared samples were characterized by XRD, FI-IR, FE-SEM, TEM, XPS, N 2 adsorption-desorption, H 2 -TPR and O 2 -TPD techniques to investigate the physical-chemical properties. A certain amount of K + doped in to LaFeO 3-δ nanotubes sample could inhibit the growth of crystallites during the calcination at a high temperature, which could prevent the destruction of macro/mesoporous tubular structure and contribute to the more contact between soot particles and active sites. Meanwhile, it could also bring about the higher oxygen vacancy density responsible for the enhancement of redox abilities. However, excessive doping of K + could lead to the collapsing of macro/mesoporous tubular structure, ascribable to the formation of low-melting compounds or eutectics with other components of the catalyst, which would have a negative influence on the catalytic performance. The performance for soot catalytic oxidation was evaluated in a temperature programmed oxidation device using O 2 (without or with NO) as oxidant. Among the as-prepared catalysts, the well-structured La 0.8 K 0.2 FeO 3-δ nanotubes catalyst is the best candidate for soot removal.
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FIBERS AND POLYMERS
·
2018
·Vol. 19
·期 5
·1004-1013
·
IF 1.353
Xu Qingbo,Ke Xiating,Ge Naiqin,Shen Liwen,Zhang Yanyan,Fu Feiya,Liu Xiangdong
When copper nanoparticles (Cu NPs) were applied as an antimicrobial agent to finish cotton fabrics, there are two issues should be solved: the oxidization and the weak adsorbability onto cotton fiber surface. In the present work, we developed a new method that can achieve both immobilization and protection of the Cu NPs at the same time. As an effective binder, thioglycolic acid (TGA) was covalently linked to cotton fiber surface via an esterification with the hydroxyl groups of cellulose, then Cu NPs were introduced on the fabric surface in the presence of a protective reagent, citric acid. Due to the doubled stabilization acts of TGA and citric acid, the Cu NPs immobilized on the fabric surface showed an excellent antibacterial effect and outstanding laundering durability. Even after 50 consecutive laundering tests, the modified cotton fabrics still showed satisfactory antibacterial ability against both S. aureus and E. coli , which the bacterial reduction rates are all higher than 96 %. It is believed that this methodology has potential applications in a wide variety of textile productions such as sportswear, socks, and medical textiles.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2018
·Vol. 319
·期 3
·869-880
·
IF 1.181
Ding Hanlin,Luo Xuegang,Zhang Xiaonuo,Yang Hao
In this work, a modified biomass material was successfully prepared by immobilization and inactivation method based on Aspergillus niger , and the obtained environmentally friendly Alginate-immobilized Aspergillus niger microsphere (AAM) exhibited a superior Th(IV) biosorption performance. The sorption kinetics and thermodynamic analysis were studied and showed that the sorption process is spontaneous and endothermic under the experimental conditions. Additionally, the maximum biosorption capacity of AAMs for Th(IV) can be of 303.95 mg g −1 at 313.15 K, which exhibited a superior biosorption capacity than the most reported other biomass materials. The results illustrated the biomaterial had good recyclability through immobilization and inactivation.
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Food & Function
·
2018
·Vol. 9
·期 12
·6155-6164
·
IF 3.289
Lang Zhang,Ya Fan,Hanwen Su,Li Wu,Yuying Huang,Lei Zhao,Bing Han,Guangwen Shu,Meixian Xiang,Jin-Ming Yang
The objective of this study was to investigate the anti-inflammatory effect of chlorogenic acid methyl ester (CME) and the molecular mechanism involved, through using non-infectious inflammation and infectious inflammation animal models as well as lipopolysaccharide (LPS)-stimulated mouse macrophage RAW264.7 cell models. Our results demonstrated that CME markedly inhibited ear swelling, paw swelling and granuloma swelling, and decreased intraperitoneal capillary permeability in non-infectious inflammation. Moreover, CME significantly alleviated the pathological damage of the lung tissue, reduced the levels of PGE2 and IL-1β in the serum and the protein expression levels of related-inflammatory factors in the lung tissue of LPS-induced mice with acute lung injury (ALI). In addition, CME affected the RAW264.7 cell cycle and inhibited the protein expressions of COX-2 and NLRP3 and prevented the phosphorylation of NF-κB p65 in RAW264.7 cells treated with LPS. These observations not only validated the anti-inflammatory effects of CME, but also revealed the underlying molecular basis, which involves the down-regulation of the expression of inflammatory factors and blockade of the COX-2/NLRP3/NF-κB signaling pathway.
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ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Minghuo Wu,Lin Fu,Yufeng Hu,Jingyun Su,Siyuan Jing,Hao Zhou,Jingjing Zhan
A multiplex-on-bead-isotope-dimethyl-labeling method was developed for the quantitative analysis of sulfonamides (SAs) in environmental water samples by liquid chromatography–high-resolution mass spectrometry (LC-HRMS). In this method, five samples could be labeled in parallel with different isotope reagents and quantified in a single LC-HRMS analysis. Magnetic solid-phase extraction (MSPE) was employed in the sample preparation to concentrate the trace-level analytes by using lab-synthesized magnetic carbon nanospheres (MCNSs). After the analytes were captured on the MCNSs, the isotope labeling was performed directly by dispersing the MCNSs in the reaction buffer (on-bead labeling). The experimental conditions for MSPE and labeling were systematically investigated. For the tested 12 SAs, a labeling efficiency of over 99% could be achieved within 20 min. The LC-HRMS separation, including equilibration, could be achieved in 6 min. By combining MSPE (enriched 200-fold), multiplex on-bead dimethyl labeling, and LC-HRMS, all the tested SAs could be reliably quantified with limits of detection (LODs) of 0.1–5 ng/L. This method was verified using fortified pond water spiked with 12 SAs (0.01–5 μg/L), and accuracies of 81–106% were achieved with good reproducibility (RSD < 10%, n = 3), which confirmed its applicability in real-sample analysis. With this method, ice samples collected at the estuary of the Daliao River in northeast China were analyzed; nine SAs (sulfanilamide, sulfapyridine, sulfamethazine, sulfamethizole, sulfachloropyridazine, sulfamethoxypyridazine, sulfameter, sulfathiazole, and sulfisoxazole) were detected at concentrations of 0–85 ng/L, and the total concentrations were in the range of 185–402 ng/L with a median value of 274 ng/L.
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Advanced Materials Interfaces
·
2018
·Vol. 5
·期 19
·1800723
·
IF 4.834
Neha Suvindran,Feiran Li,Yunlu Pan,Xuezeng Zhao
Biomimicry elucidates nature's faultless synchronization of structure with function inspiring researchers to create designs that can achieve maximum performance with minimalistic resource exhaustion. Nature has evolved the invasive species Tradescantia pallida ( T. pallida ) with the ability to survive in drought lands. Since this species requires humidity to survive in those conditions it can be inferred that the T. pallida partakes of foliar atmospheric water harvesting. Herein, the wettability is tested with the study establishing that the leaf exhibits para-hydrophobicity while demonstrating a static contact angle of 165°, whereas the morphological characterization reveals a complex hierarchical sculpturing with macroscale trichomes and parallel venations. Moreover, it is identified that the foliar water uptake occurs via the para-hydrophobic surface and the hydrophobic trichomes subsequently guiding the water along the parallel channels creating a leaf that has an efficient dual way water harvesting system. These features render it capable of surviving in any habitat that validates nature's perfect unification of structure and function. Such multifunctional surfaces are a rarity thereby making them desirable for smart water harvesting designs. Thus inspired, a replica is developed which mimics the wettability with functional artificial trichomes and a potential dual way patterned water harvesting concept is presented.
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