Analytical Methods
·
2015
·Vol. 7
·期 5
·1971-1976
·
IF 1.821
Yahong Chen,Gongke Li,Yufei Hu
In this paper, a novel electrochemical method is proposed for the determination of 5-hydroxytryptophan (5-HTP) based on a carbon nanosheets (CNSs)-modified electrode. The CNSs were prepared by a one-step flowing electrolysis using a home-made device. The surface morphology and composition of the CNSs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The cyclic voltammetry method was used to study the electrochemical behavior of 5-HTP on the CNSs-modified electrode. The results suggested that the modified electrode exhibited high electrocatalytic activity, and that the anodic peak current of 5-HTP was significantly enhanced on the modified electrode. A differential pulse voltammetry method was developed for the determination 5-HTP at the modified electrode. In the optimum experimental conditions, the linear calibration range varied from 5 × 10−8 mol L−1 to 1 × 10−6 mol L−1, with a detection limit of 3 × 10−8 mol L−1. The proposed method was further successfully applied for the determination of 5-HTP in rats' brain tissue samples, with the recovery ranging from 90.3% to 98.0%.
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ANALYTICAL CHEMISTRY
·
2013
·
IF 5.695
Yuling Hu,Zelin Huang,Jia Liao,Gongke Li
A facile and efficient strategy about the synthesis of a novel kind of hybrid magnetic metal–organic framework (MOF)-5 via chemical bonding assembly was reported. The covalent bonding established between the amino functionalized Fe3O4 nanoparticles and the surface of the metal organic framework improved the chemical stability and structure uniformity of the hybrid microcrystals. Combination of MOF-5 with Fe3O4 nanoparticles allows for facile withdrawal of the porous materials by magnetic decantation. The powder X-ray diffraction patterns of the hybrid magnetic MOF-5 showed the structure of the metal organic framework was not disturbed with the decoration of magnetic nanoparticles. The as-synthesized materials combine the favorable attributes of both magnetic characteristics of Fe3O4 nanoparticles and high porosity of metal organic framework, making them excellent candidates as adsorbents for magnetic enrichment of trace analytes. Their potential applications were explored by preconcentrating polycyclic aromatic hydrocarbons and gibberellic acids from environmental, food, and plant samples prior to gas chromatography–mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively. The results showed that the magnetic MOF-5 exhibited superior enrichment capacity for both of these nonpolar and polar analytes. The method demonstrated good precision (relative standard deviations (RSDs) of 1.7–9.7%), low detection limits (0.91–1.96 ng·L–1 for polycyclic aromatic hydrocarbons and 0.006–0.08 μg L–1 for gibberellic acid), and good linearity (correlation coefficients higher than 0.9949). The RSDs of batch-to-batch extraction were 2.9–11.2%. The magnetic MOF-5 was robust enough for repeatable use without damage of extraction performance.
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MICROCHIMICA ACTA
·
2013
·Vol. 180
·期 11
·1051-1057
·
IF 3.434
Wang Ai-Jun,Guo Han,Zhang Ming,Zhou Dan-Ling,Wang Rui-Zhi,Feng Jiu-Ju
We have developed a simple, sensitive and selective colorimetric method for the detection of cadmium(II) (Cd 2+ ) using gold nanoparticles modified with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole. Organic solvents or additives are not required. It is found that Cd 2+ induces the aggregation of the modified Au-NPs via chelation, leading to a color change from red to blue. This change can be seen with bare eyes, and monitored by UV–vis spectroscopy, transmission electron microscopy and dynamic light scattering. The detection limit is 30 nM (at a signal-to-noise ratio of 3). The new approach was successfully applied to the detection of Cd 2+ in spiked samples of tap water and lake water, and the results agree well with those obtained by flame atomic absorption spectroscopy.
A simple, sensitive and selective colorimetric method was developed for the detection of Cd 2+ , where 4-amino-3-hydrazino-5-mercapto-1,2,4-triazol (AHMT) modified gold nanoparticles (AuNPs) were used as optical probes. The presence of Cd 2+ induced the aggregation of the AHMT-AuNPs through the chelation process. This approach was successfully applied for the detection of Cd 2+ in spiked samples of tap water and lake water.
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RSC Advances
·
2014
·Vol. 4
·期 45
·23797-23806
·
IF 3.708
Yunlei Zhang,Jianming Pan,Yongsheng Yan,Weidong Shi,Longbao Yu
Based on halloysite nanotubes (HNTs), precipitation polymerization and Pickering emulsion polymerization were firstly adopted to synthesize two composites i.e. HNTs–polystyrene(PSt)–polydivinylbenzene(DVB)(I) and HNTs–PSt–PDVB(II), respectively. After sulfonation by 98% H2SO4, two polymeric solid acid catalysts i.e. HNTs–PSt–PDVB–SO3H(I) and HNTs–PSt–PDVB–SO3H(II) were successfully prepared for conversion of one-pot cellulose to 5-hydroxymethylfurfural (HMF) in an ionic liquid 1-ethyl-3-methyl-imidazolium chloride ([EMIM]-Cl). Characterization of two catalysts showed that HNTs–PSt–PDVB–SO3H(I) possessed superior hydrophobicity, content of –SO3H groups, and total acidic amounts to those of HNTs–PSt–PDVB–SO3H(II), but with less very strong acidic sites and non-uniform morphology. Then the amount of the catalysts, reaction time and reaction temperature were optimized for cellulosic conversion over the two catalysts, and a maximum yield of 28.52% for HNTs–PSt–PDVB–SO3H(I) and 32.86% for HNTs–PSt–PDVB–SO3H(II) under the optimized conditions was obtained, indicating very strong acidic sites played a key role in cellulose conversion. In addition, the two as-prepared catalysts could be very easily recycled at least five times without significant loss of catalytic activity.
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JOURNAL OF CHEMICAL THERMODYNAMICS
·
2017
·
IF 2.726
Qing-Qing Zhao,Xiao-Hui Wu,Ning Ren,Jian-Jun Zhang,Li-Na Geng
Two novel lanthanide complexes with the general formula [Ln(2-Br-5-MOBA) 3 (2,2′-DIPY)] 2 (Ln = Pr(1), Dy(2); 2-Br-5-MOBA = 2-bromine-5-methoxybenzoate; 2,2′-DIPY = 2,2′-bipyridine) have been successfully synthesized and characterized. The complexes 1 and 2 are isostructural and nine-coordinated with distorted monocapped square antiprismatic coordination geometry by the single-crystal X-ray diffraction analyses. Two complexes are all assembled into the 1D, 2D, 3D supramolecular structures by C H⋯O hydrogen bonding and π–π stacking interactions. The thermal decomposition mechanism for title complexes were obtained by TG/DSC-FTIR technology. The molar heat capacities of the complexes 1 and 2 are measured by a DSC instrument over the temperature range from 263.15 K to 365.15 K. On the basis of the fitted polynomial and thermodynamic equations, the smoothed values of heat capacities and thermodynamic functions ( H T - H 298.15K ), and ( S T - S 298.15K ) of the two complexes are calculated. In addition, the fluorescence spectra indicate that the complex 2 exhibits the characteristic emission of Dy(III) ion ( 4 F 9/2 → 6 H 13/2–15/2 ).
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Lixi Chen,Ying Wang,Xiangyang Yuan,Yi Ren,Ning Liu,Lihua Yuan,Wen Feng
Three phosphine oxide functionalized pillar[5]arenes (POP5A) were evaluated for the extraction of uranyl ion from nitric acid feed solutions in room temperature ionic liquid (RTIL), 1-n-octyl-3-methylimidazolium hexafluorophosphate (C 8 mimNTf 2 ). The host-guest interaction between POP5A and C 8 mim + for the formation of [POP5A C 8 mim] + complex was evidenced by 1D and 2D proton NMR spectroscopy and mass spectra technique before extraction, and also supported by theoretical calculation. High extraction efficiency and selective separation of UO 2 2+ were achieved with the ligand bearing longer spacer exhibiting best solvent extraction performance. The distribution ratios of U(VI) in RTIL were significantly enhanced in the range of 0.1–1.8 M HNO 3 as compared with organic diluent. The extracted species were ascertained from the slope analysis method as well as Job plots method, and a supramolecular cation-exchange mechanism involving competitive host-guest interactions was found to dominate the extraction process. This extraction system was also examined for its ability towards extraction of lanthanides and Th 4+ . The results revealed an excellent selectivity towards UO 2 2+ over other metal ions. Stripping experiments showed almost a complete back extraction of UO 2 2+ within four stages. With high selectivity towards UO 2 2+ and efficient back extraction, this new POP5A-RTIL extraction system shows promise for future application of uranium recovery.
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CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Xiaoling Zhang,Mingbao Feng,Liansheng Wang,Ruijuan Qu,Zunyao Wang
Recently, the toxicity of sunscreen has received extensive attention due to their potential endocrine disrupting effect. In the present study, nitrogen and sulfur co-doped multi-walled carbon nanotubes loaded CuFe 2 O 4 (NS-CNTs/CuFe 2 O 4 ) catalyst was rationally designed and synthesized by co-precipitation method for the degradation of 2-phenylbenzimidazole-5-sulfonic acid (PBSA, a typical sunscreen addition). The catalyst was fully characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen gas uptake, and X-ray photoelectron spectroscopy. Then the kinetics, pathways and mechanisms of catalytic degradation of PBSA were studied in NS-CNTs/CuFe 2 O 4 activated peroxymonosulfate (PMS) solution. The catalyst showed high catalytic activity, stability and reusability in PBSA removal. The results of electron paramagnetic resonance (EPR) and quenching experiments suggested that sulfate radicals (SO 4 − ) predominated in the activation of PMS by NS-CNTs/CuFe 2 O 4 . The synergistic effect between CuFe 2 O 4 and NS-CNTs was proposed in PMS activation. In addition, eight degradation intermediates of PBSA were identified by liquid chromatography mass spectrometry (LC–MS), and degradation pathways were further proposed. Overall, this study provides insights of PBSA removal by NS-CNTs/CuFe 2 O 4 activated PMS at ambient temperature.
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JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 4
·1007-1016
·
IF 1.624
Zhao Xinhong,Zhang Xiaoxiao,Hao Zhixin,Gao Xiangping,Liu Zhong
To synthesize zeolites in a safe and cost-saving manner is the first and the most important task for zeolite application in industry. In the present work, FeAPO-5 aluminophosphate molecular sieve with high iron content was ionothermally synthesized by microwave irradiation at ambient pressure using low dosage of eutectic mixture as the solvent. The influences of seed crystals and mechanochemical pretreatment on the synthesis of FeAPO-5 were investigated in detail. The resultant relatively pure FeAPO-5 molecular sieves were characterized by XRD, ICP-AES, SEM, N 2 physisorption and UV–Vis diffuse reflectance spectrometer, and their catalytic performances were studied using phenol hydroxylation as a probe reaction. The XRD results revealed that pure FeAPO-5 can be readily obtained from mechanochemically pretreated reactants, regardless of whether or not the seed crystals were added. The ICP-AES measurements suggested that only by using specific seed crystals can pure FeAPO-5 molecular sieve with high iron content be synthesized. The SEM analysis implied that seed crystals may play a role of morphology-directing agent in these syntheses. The catalytic results demonstrated that longer pronounced induction period were only observed over those FeAPO-5 catalysts with sole framework iron species. The different catalytic activity among five selected catalysts was largely determined by their different densities of framework iron species, while the selectivity towards dihydroxybenzene was mainly controlled by the diffusion path length. Under given reaction conditions, FeAPO-5 catalyst with up to 6.79 wt% of iron content gave 42.0% dihydroxybenzene yield with a selectivity of 94.1%.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 19
·1-11
·
IF 2.8
Shen Xuri,Kong Jinfang,Wang Fengchao,Zhang Canyun,Li Lan,Chen Jin,Yang Jing,Sun Yu
Two-dimensional (2D) Cu 2+ –Mn 2+ co-doped CsPb 2 (ClBr) 5 nanocrystals (NCs) with various Cu/Mn molar ratios were synthesized by a simple one-pot method at room temperature. Additionally, we encapsulated C 3 H 9 SiCl to protect the co-doped CsPb 2 (ClBr) 5 NCs from moisture. The analysis of the structure and composition confirmed the phase and chemical composition of the 2D co-doped CsPb 2 (ClBr) 5 NCs. Steady-state and time-resolved photoluminescence (PL) spectroscopy revealed the enhanced optical properties of the 2D co-doped CsPb 2 (ClBr) 5 NCs. Meanwhile, the optical properties of Cu 2+ –Mn 2+ co-doped NCs presented the good thermal stability even after 36 days. The photoluminescence quantum yields (PLQYs) related to the Mn 2+ emission of the 2D co-doped CsPb 2 (ClBr) 5 NCs increased to 97.36% at a Cu/Mn molar ratio of 0.05/1. Furthermore, a prototype white light-emitting device (WLED) was successfully assembled by combining orange‒red Cu 2+ –Mn 2+ co-doped CsPb 2 (ClBr) 5 NCs, a CsPbBr 3 film, and a 365 nm commercial UV chip; this prototype confirms its potential for a wide range of applications in general lighting.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yumei Zhu,Jinlv Wei,Jia Wu,Rong Chen,Panagiotis Tsiakaras,Shibin Yin
The development of catalysts with suitable adsorption behavior for the reaction molecules and the elucidation of their internal structure-adsorption-catalytic activity relationships are crucial for the electrooxidation of 5-hydroxymethylfurfural (HMF). In this work, NiO-CuO heterostructures with a spontaneous built-in electric field (BEF) are specifically designed and used to regulate the OH − adsorption site for freeing up the active site of HMF for the HMF oxidation reaction (HMFOR). The mechanism driving electron pumping/accumulation of the BEF is examined by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Electrochemical data and theoretical calculations show that BEF modulates the adsorption energy and adsorption site of substrate molecules, thereby enhancing the performance of HMFOR and hydrogen evolution reaction (HER). Notably, the NiO-CuO electrode demonstrates high 2,5-Furandicarboxylic acid (FDCA) selectivity (99.76 %) and generation rate (13.79 mmol gcat −1 h −1 ). It only requires 1.33 V to obtain a current density of 10 mA cm −2 for HMFOR-coupled H 2 evolution. This research introduces a novel approach by regulating the adsorption of reactive molecules for HMFOR-assisted H 2 evolution.
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Drug Delivery and Translational Research
·
2024
·
IF 5.7
Chen Siwei,Huang Hongwu,Li Qi,Cai Jia,Miao Zhuolin,Xie Peikang,Tang Shengsong,He Dongxiu
5-Fluorouracil (5-FU) is commonly used as a chemotherapeutic drug for advanced HCC. However, the effectiveness of 5-FU is limited by the emergence of resistance and poor targeting efficiency. Combining 5-FU with natural compounds has shown promise in HCC treatment. In this study, we prepared carrier-free nanoparticles (GEN-Cu-GEN@FUA) containing 5-FU and genistein (GEN) in a synergistic ratio via a green synthesis procedure. The resulting GEN-Cu-GEN@FUA nanoparticles had a spherical or near spherical shape, a dynamic size of 129.3 ± 40.1 nm, and a high drug loading content of approximately 21.40% (5-FU) and 61.48% (GEN). These nanoparticles exhibited approximately 3.6-fold lower IC50 value than 5-FU alone in Bel-7402 cells and resulted in a 3.7-fold greater reduction in tumor weight compared to 5-FU alone in Bel-7402 tumor-bearing BALB/c mice. Importantly, the nanoparticles showed negligible systemic toxicity due to their synergistic effect on cancer cell dysfunction and significant amplification of intracellular glutathione consumption. Our findings suggest that the developed carrier-free nanomedicines offer a highly promising platform for the co-delivery of genistein (GEN) copper(II) complexes and 5-FU, with easy fabrication and great potential for clinical translation in HCC synergistic therapy. Graphical abstract
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Journal of Energy Storage
·
2024
·
IF 8.9
Jinping Mu,Xiaohui Li,Rui He,Lijing Sun,Xue Bai,Lihui Zhang,Peng Liu,Zhenfa Liu,Jing Gao,Aijia Wei
High-voltage lithium-ion batteries (LIBs) with LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode are considered promising energy sources due to their high energy density . However, enhancing the stability of the electrode/electrolyte interface remains critical for the practical application of LIBs. In this work, lithium-containing inorganic phosphates (LiPO 3 , Li 3 PO 4 , and LiH 2 PO 4 ) were used as multifunctional inorganic additives to improve the stability of the electrode/electrolyte interface in 5.0 V, LNMO-based LIBs with carbonate-based electrolytes. Based on theoretical calculations and experimental evaluations of the electrochemical performance , LiPO 3 was selected as the optimal additive for further study in LNMO/Li and LNMO/Li 4 Ti 5 O 12 cells. The LNMO/Li half-cells with LiPO 3 delivered an initial discharge capacity of 108.8 mAh∙g −1 and retained a capacity of 94.9 % after 500 cycles at 5C, compared to 75.1 mAh∙g −1 and 79.4 % for the standard electrolyte. The increased cycling stability was ascribed to the ability of the multifunctional, film-forming LiPO 3 additive to form stable interfacial films on both the cathode and anode , thus, inhibiting side reactions between the electrodes and electrolyte. Moreover, as an HF scavenger, LiPO 3 reduced the HF content in the electrolyte to ensure the structural integrity of LNMO and inhibit the dissolution of transition metal ions . In the LNMO/Li 4 Ti 5 O 12 full cells, the addition of LiPO 3 effectively enhanced the cycling performance, and the capacity retention after 400 cycles at 5C was 79.1 %, compared to only 12.3 % for the standard electrolyte. Considering its simplicity, low cost, and feasibility, the addition of LiPO 3 as a multifunctional electrolyte additive showed excellent prospects for commercial applications.
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