JOURNAL OF SEPARATION SCIENCE
·
2013
·Vol. 36
·期 12
·1996-2002
·
IF 2.591
Jie Lei,Xiangmin Zhang
Columns for open tubular capillary electrochromatography, coated with a mixed-mode (RP/ion-exchange) stationary phase, were prepared by using the sol–gel method. The synthetic procedure was optimized by changing the ratios of tetraethoxysilane, octyltriethoxysilane, and 3-aminopropyltriethoxysilane in the initial sol. SEM studies reveal that a coating with about 400 nm thickness can be obtained. The inner surface properties of these capillaries were probed by measuring the EOF as a function of pH. The surface of this stationary phase contains octyl, amine, and residual silanol moieties; the amine and silanol groups determine the net charge on the inner surface of the capillary and can produce a switchable EOF (anodal/cathodal). The performances of the columns were evaluated by open tubular capillary electrochromatography using a wide range of compounds (polycyclic aromatic hydrocarbons, aromatic acids, and aromatic amines).
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JOURNAL OF CHROMATOGRAPHY A
·
2012
·
IF 4.531
Yan-Yan Fu,Cheng-Xiong Yang,Xiu-Ping Yan
Metal-organic framework MIL-100(Fe) was explored as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography. Two groups of analytes (benzene, toluene, ethylbenzene, naphthalene and 1-chloronaphthalene; aniline, acetanilide, 2-nitroaniline and 1-naphthylamine) were used to test the separation performance of MIL-100(Fe) in the reverse-phase mode, while the isomers of chloroaniline or toluidine were employed to evaluate its performance in the normal-phase mode. The MIL-100(Fe) packed column gave a baseline separation of all the tested analytes with good precision. The separation was controlled by negative enthalpy change and entropy change in the reverse-phase mode, but positive enthalpy change and entropy change in the normal-phase mode. The relative standard deviations of retention time, peak area, peak height, and half peak width for eleven replicate separations of the tested analytes were 0.2–0.7%, 0.5–3.6%, 0.6–2.3% and 0.8–1.7%, respectively. The mesoporous cages, accessible windows, excellent chemical and solvent stability, metal active sites and aromatic pore walls make MIL-100(Fe) a good candidate as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2014
·
IF 2.129
Jiao Zhao,Yunhui Lu,Chongyang Fan,Jun Wang,Yaling Yang
A novel and simple method for the sensitive determination of trace amounts of nitrite in human urine and blood has been developed by combination of cloud point extraction (CPE) and microplate assay. The method is based on the Griess reaction and the reaction product is extracted into nonionic surfactant Triton-X114 using CPE technique. In this study, decolorization treatment of urine and blood was applied to overcome the interference of matrix and enhance the sensitivity of nitrite detection. Multi-sample can be simultaneously detected thanks to a 96-well microplate technique. The effects of different operating parameters such as type of decolorizing agent, concentration of surfactant (Triton X-114), addition of (NH 4 ) 2 SO 4, extraction temperature and time, interfering elements were studied and optimum conditions were obtained. Under the optimum conditions, a linear calibration graph was obtained in the range of 10–400 ng mL −1 of nitrite with limit of detection (LOD) of 2.5 ng mL −1 . The relative standard deviation (RSD) for determination of 100 ng mL −1 of nitrite was 2.80%. The proposed method was successfully applied for the determination of nitrite in the urine and blood samples with recoveries of 92.6–101.2%.
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Journal of Materials Chemistry C
·
2015
·Vol. 3
·期 11
·2693-2701
·
IF 4.696
Junjie Li,Chunhua Lai,Xiongzhi Xiang,Lei Wang
As representative conjugated polymers, the physical properties, such as electric conductivity and electro-optic properties, of poly-Schiff bases (PSBs) have been widely investigated. However, to date, the thermoelectric (TE) properties of PSB or related polymers remain unreported. In this study, PSB with a donor–acceptor structure (PSB(A)) was synthesized and was blended with different fillers to prepare polymer–inorganic TE composites. For comparison, PSB with the common structure (PSB(B)) was also synthesized, and PSB(B)–graphite composites were fabricated. The PSB(A)/graphite composites exhibited a higher power factor of 10.2 μW m−1 K−2 compared with 4.5 μW m−1 K−2 of the PSB(B)/graphite composites at the same doping level. The effects of different fillers on the TE properties of the PSB(A)-based composites were investigated in detail, and the highest TE figure of merit, ZT = 2.53 × 10−3, was obtained. The results show that excellent TE materials could be produced by preparing polymer–inorganic TE composites using novel conducting polymers with a special structure (e.g., donor–acceptor structure) and conducting fillers.
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JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Chengjiang Zhang,Gongke Li,Zhuomin Zhang
Covalent organic polymers (COPs) connected by covalent bonds are a new class of porous network materials with large surface area and potential superiority in sample pretreatment. In this study, a new hydrazone linked covalent organic polymer (HL-COP) adsorbent was well-designed and synthesized based on a simple Schiff-base reaction. The condensation of 1,4-phthalaldehyde and 1,3,5-benzenetricarbohydrazide as organic building blocks led to the synthesis of HL-COP with uniform particle size and good adsorption performance. This HL-COP adsorbent with high hydrophobic property and rich stacking π electrons contained abundant phenyl rings and imine ( C N) groups throughout the entire molecular framework. The adsorption mechanism was explored and discussed based on π–π affinity, hydrophobic effect, hydrogen bonding and electron–donor–acceptor (EDA) interaction, which contributed to its strong recognition affinity to target compounds. Enrichment factors were 305–757 for six Sudan dyes by HL-COP micro-solid phase extraction (μ-SPE), indicating its remarkable preconcentration ability. Furthermore, the adsorption amounts by HL-COP μ-SPE were 1.0–11.0 folds as those by three commonly used commercial adsorbents. Then, HL-COP was applied as adsorbent of online μ-SPE coupled with high performance liquid chromatography (HPLC) for enrichment and analysis of trace Sudan dyes in food samples with detection limit of 0.03–0.15 μg/L. The method was successfully applied for online analysis of chilli powder and sausage samples. Sudan II and Sudan III in one positive chilli powder sample were actually found and determined with concentrations of 8.3 and 6.8 μg/kg, respectively. The recoveries of chilli powder and sausage samples were in range of 75.8–108.2% and 73.8–112.6% with relative standard deviations of 1.2–8.5% and 1.9–9.4% ( n = 5), respectively. The proposed method was accurate, reliable and convenient for the online simultaneous analysis of trace Sudan dyes in food samples.
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POLYMER BULLETIN
·
2016
·Vol. 74
·期 8
·3109-3121
·
IF 1.371
Sun Wei,Zheng Yan,Zhang Xingyuan
Novel waterborne polyurethane (WPU) with side-chained Phenylazonaphthalene group was prepared by step-growth addition polymerization between isophorone diisocyanate (IPDI), polytetramethylene ether glycol (PTMG), 2, 2-dimethylol propionic acid (DMPA) and a self-made azo diol, N , N -(2-hydroxyethyl)-4-phenylazo naphthylamine (HPN), as a chain extender to partially substitute for 1, 4-butanediol (BDO). 1 H nuclear magnetic resonance spectra ( 1 H NMR), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet–Visible (UV–Vis) spectroscopy were used to research the properties of HPN and HPN-WPU. The WPU latex presented obvious trans–cis photoisomerization during UV radiation and the absorption wavelength of the HPN exhibited a blue shift after attached into polyurethane chains. It needed longer irradiated time to finish isomerization due to the emulsion aggregated states, comparing with phenylazonaphthalene monomer solution and WPU dilute solution.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2016
·
IF 2.822
Yuehong Pang,Yi Zhang,Wanyu Li,Hongliu Ding,Xiaofang Shen
A novel method was developed for the synergetic accumulation and simultaneous determination of naphthol isomers (α-N and β-N) at electrochemically reduced graphene oxide modified glassy carbon electrode (E-rGO/GCE). One-step electrochemical reduction was employed for the fabrication of E-rGO/GCE, then the modified material was characterized by scanning electron microscope, Raman spectroscopy and Fourier transform infrared spectroscopy. Electrochemical behavior of naphthol isomers at E-rGO/GCE shows that the sensitivity of the isomers could be increased due to the synergistic effect of π–π conjugating and electrochemical accumulation. The oxidation peaks of α- and β-naphthol could be completely separated and the isomers were simultaneously detected with the linear ranges of 5–400 nM and 0.5–20 μM for α-N, 5–350 nM and 0.5–20 μM for β-N. The detection limits of α-N and β-N were 1.01 nM and 0.43 nM (S/N = 3), and the corresponding sensitivity were 0.0097 μA/μM and 0.0113 μA/μM, respectively. More importantly, the naphthol isomers electrochemical sensor on E-rGO film with synergistic effect can be expected to result in significant improvements in the sensor performance and the developed method has been successfully applied to human urine sample with a satisfactory result.
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JOURNAL OF CHROMATOGRAPHY A
·
2016
·
IF 3.926
Li-Shun Zhang,Pei-Yao Du,Wen Gu,Qing-Li Zhao,Yan-Ping Huang,Zhao-Sheng Liu
A new lanthanide metal-organic frameworks NKU-1 have successfully incorporated into poly (BMA- co -EDMA) monolith and evaluated by capillary electrochromatography (CEC). Lanthanide metal-organic frameworks [Eu 2 (ABTC) 1.5 (H 2 O) 3 (DMA)] (NKU-1) were synthesized by self-assembly of Eu(III) ions and 3,3′,5,5′-azo benzene tetracarboxylic acid ligands have been fabricated into poly(BMA- co -EDMA) monoliths. 1-Butyl-3-methylimidazolium tetrafluoroborate and N , N -dimethylformamide were developed as binary porogen obtaining homogeneous dispersibility for NKU-1 and high permeability for monolithic column. The successful incorporation of NKU-1 into poly(BMA- co -EDMA) was confirmed and characterized by FT-IR spectra, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer area scanning, and transmission electron microscopy. Separation ability of the NKU-1-poly (BMA- co -EDMA) monoliths was demonstrated by separating four groups of analytes in CEC, including alkylbenzenes, polycyclic aromatic hydrocarbon, aniline series and naphthyl substitutes. Compared with bare monolithic (column efficiency of 100,000 plates/m), the NKU-1-poly (BMA- co -EDMA) monoliths have displayed greater column efficiency (maximum 210,000 plates/m) and higher permeability, as well as less peak tailing. The results showed that the NKU-1-poly (BMA- co -EDMA) monoliths are promising stationary phases for CEC separations.
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Polymer Chemistry
·
2016
·
IF 5.687
Jiangang Xiao,Jianzhong Du
Multifunctional statistical copolymers can be simply synthesized in one step without tedious and time-consuming procedures. In addition, the fuzzy boundary between different functional groups in the statistical copolymers can facilitate the fabrication of new functional nanomaterials. Herein, we designed a novel multifunctional vesicle based on a statistical copolymer, poly[[2-hydroxy-3-(naphthalen-1-ylamino)propyl methacrylate]-stat-[2-(diethylamino)ethyl methacrylate]] [P(HNA21-stat-DEA35)] which can be synthesized by reversible addition–fragmentation transfer (RAFT) polymerization in one step. The HNA moiety is designed for capturing polycyclic aromatic hydrocarbons (PAHs) by π–π stacking, while the DEA moiety is engineered to immobilize gold nanoparticles for facilitating the reduction of 4-nitrophenol (4-NP) in aqueous solution. This vesicle showed excellent ability in water remediation by absorbing PAHs and accelerating the reduction of 4-nitrophenol (4-NP). Overall, this multifunctional statistical copolymer vesicle provides a new insight for designing multifunctional water remediation materials.
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TALANTA
·
2016
·
IF 4.035
Li-Shun Zhang,Qing-Li Zhao,Xin-Xin Li,Xi-Xi Li,Yan-Ping Huang,Zhao-Sheng Liu
A hybrid monolith incorporated with mesoporous molecular sieve MCM-41 of uniform pore structure and high surface area was prepared with binary green porogens in the first time. With a mixture of room temperature ionic liquids and deep eutectic solvents as porogens, MCM-41 was modified with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and the resulting MCM-41-MPS was incorporated into poly (BMA-co-EDMA) monoliths covalently. Because of good dispersibility of MCM-41-MPS in the green solvent-based polymerization system, high permeability and homogeneity for the resultant hybrid monolithic columns was achieved. The MCM-41-MPS grafted monolith was characterized by scanning electron microscopy, energy dispersive spectrometer area scanning, transmission electron microscopy, FT-IR spectra and nitrogen adsorption tests. Chromatographic performance of MCM-41-MPS grafted monolith was characterized by separating small molecules in capillary electrochromatography , including phenol series, naphthyl substitutes, aniline series and alkyl benzenes. The maximum column efficiency of MCM-41-MPS grafted monolith reached 209,000 plates/m, which was twice higher than the corresponding MCM-41-MPS free monolith. Moreover, successful separation of non-steroidal anti-inflammatory drugs and polycyclic aromatic hydrocarbons demonstrated the capacity in broad-spectrum application of the MCM-41-MPS incorporated monolith. The results indicated that green synthesis using room temperature ionic liquid and deep eutectic solvents is an effective method to prepare molecular sieve-incorporated monolithic column.
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RSC Advances
·
2017
·Vol. 7
·期 5
·2650-2657
·
IF 3.108
Zhike Wang,Cunling Ye,Lingyun Chen,Haili Wu
Adsorptive removals of naphthols are often interfered by some coexisting anions of aqueous solutions. In this work, 1-vinyl-3-octadecylimidazolium cations and p-styrenesulphonate anions were chemically co-modified on silica (denoted as Sil-PImC18-SS) via the click chemistry reaction and were characterized. This material was created with the aim to explore the feasibility of removal of 1-naphthol (1-NAP) and 2-naphthol (2-NAP) from aqueous solutions. The prepared Sil-PImC18-SS was used as an adsorbent to remove 1-NAP and 2-NAP from aqueous solutions and the effects of various variables for the adsorption of 1-NAP and 2-NAP were systematically studied. Among the coexisting anions tested, 0.2 mol L−1 background NaCl or Na2SO4 aqueous solutions had no significant effect on the adsorption of 1-NAP and 2-NAP. The adsorption behaviors of 1-NAP and 2-NAP were well described by the pseudo-second order kinetic and the Dubinin–Radushkevich models with the maximum adsorption capacities of 84.4 mg g−1 and 71.9 mg g−1 for 1-naphthol and 2-naphthol, respectively. The adsorption was a spontaneous and exothermic process, and an adsorption mechanism was speculated to be the cooperative contributions from the hydrophobic interaction, hydrogen bonding interaction, and π–π stacking. Thus, Sil-PImC18-SS can be potentially used as an effective adsorption material for naphthol pollutant removal from the water environment.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Cheng Yang,Yanmei Shi,Lixin Li,Zhihong Chen,Di Zhao,Weixia Zhu,Kai Hu
Bisphenol A (BPA) is widespread in the environment and has a serious impact on human body. In this study, a novel magnetic metal-organic frameworks@Ti 3 C 2 T x composite, noted as Fe 3 O 4 @Ti 3 C 2 T x /MOF, was prepared and used as adsorbent for the removal of BPA from environmental water. The adsorption parameters that affecting the removal efficiency of BPA, such as solution pH, contact time, adsorbent dosage, co-existing inorganic ions, ionic strength, and humic acid were investigated in detail. Accordingly, the removal efficiency of BPA by Fe 3 O 4 @Ti 3 C 2 T x /MOF was as much as 95 %. Adsorption studies showed that the proposed composite can provide a maximum adsorption capacity of 547.43 mg g −1 for BPA within 5 min, which was superior to most of the reported adsorbents. The adsorption process was consistent with the pseudo-second-order kinetics (K 2 , 1.1063 μg mg −1 min −1 ) and Freundlich isotherm model, indicating that the adsorption was depended by chemisorption and the heterogeneous surface. Furthermore, the thermodynamic results demonstrated the exothermic nature of the adsorption process (ΔH θ = −34.84 kJ mol −1 ). Most importantly, the magnetic properties of the Fe 3 O 4 @Ti 3 C 2 T x /MOF make it easy to collect, so it can be regenerated and reused for at least 4 cycles without significant loss of adsorption efficiency. Overall, the proposed composite can be applied to the efficient removal of BPA from water samples and could be potentially applicable for practical wastewater treatment.
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