ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Xingru Hu,Chaohai Wang,Jiansheng Li,Rui Luo,Chao Liu,Xiuyun Sun,Jinyou Shen,Weiqing Han,Lianjun Wang
Developing novel coating materials for fast and sensitive solid-phase microextraction (SPME) is highly desired but few are achieved. In this work, a new material of metal–organic framework (MOF)-derived hollow carbon nanocubes (HCNCs) was prepared as a fiber coating material for SPME. The HCNC-coated fiber (denoted as HCNCs-F) exhibited a better enrichment performance than solid carbon nanocube (SCNC)-coated fiber (denoted as SCNCs-F) and commercial fibers based on the abundant active sites of the hollow structure, hydrophobic interactions, and π–π interactions. Moreover, because of the reduced mass-transport lengths of the hollow mesoporous structure, the HCNCs-F demonstrated a faster mass transfer compared with the SCNCs-F. The HCNCs-F was used to determine the six hydrophobic polycyclic aromatic hydrocarbons (PAHs) with wide linear ranges (10–2000 ng L–1 for naphthalene and 5–2000 ng L–1 for the other five analytes), good reproducibility (relative standard deviation < 8.8%), and low detection limits (0.03–0.70 ng L–1). Finally, the HCNCs-F was successfully applied for the determination of PAHs from the real water samples. It can be concluded from the results that MOF-derived hollow carbon materials are promising candidates for the fast SPME and can be used for practical applications in analytical chemistry.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2018
·Vol. 10
·期 41
·5014-5024
·
IF 2.073
Xuexiang Shi,Ning Li,Di Wu,Na Hu,Jing Sun,Xuxia Zhou,Yourui Suo,Guoliang Li,Yongning Wu
A novel magnetic covalent organic framework (Fe3O4@COF(TpDA)) material possessing a large surface area and high and regular porosity was constructed via a facile strategy and applied as a magnetic solid phase extraction sorbent for the determination of trace polycyclic aromatic hydrocarbons in edible oil and grilled meats prior to high performance liquid chromatography with diode array detection. The obtained materials were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption isotherms and vibrating sample magnetometry. The prepared Fe3O4@COF(TpDA) materials showed some attractive features including a large surface area (180.20 m2 g−1) and high saturation magnetization (62.28 emu g−1). The experimental parameters affecting the extraction performance including the type of eluent, amount of sorbent, and adsorption and desorption times were optimized. Under the optimized conditions, the adsorption equilibrium for polycyclic aromatic hydrocarbons could be achieved in only 10 min. The proposed method achieved low limits of detection (0.03–0.73 μg L−1 for LODs and 0.10–2.43 μg L−1 for LOQs) and good linearity (R ≥ 0.9937). The obtained materials were successfully applied to enrich polycyclic aromatic hydrocarbons in edible oil and grilled meats and showed good accuracy with recoveries in the range of 85.5–104.2%. Furthermore, the proposed method was also evaluated by different adsorption kinetic theories, and the pseudo-second-order model can explain the adsorption kinetics. The proposed method is facile, rapid, effective and selective for determination of PAHs in food samples.
✓ 已验证
产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2018
·
IF 2.88
Zhe Yang,Tingting Liu,Yutian Wang,Yuanyuan Yuan,Fengkai Shang
Interference-free determination of polycyclic aromatic hydrocarbons (PAHs) in water pollution is proposed based on third-order correction algorithms with quadrilinear component modeling applied to the constructed four way fluorescence excitation–emission-sample data array with higher accuracy and better predictive ability than second-order (three-dimension) correction. Alternating weighted residue constraint quadrilinear decomposition (AWRCQLD), quadrilinear parallel factor analysis (4-PARAFAC), alternate penalty quadrilinear decomposition (APQLD) and alternate penalty trilinear decomposition (APTLD) are applied to acenaphthene (ANA), naphthalene (NAP) and fluorene (FLU) respectively. Fulvic acid affects PAHs determination seriously in real-world situation, so it is simulated as an interfering agent. Excitation-emission fluorescence matrixes (EEMs) of PAHs are measured at different volumes of fulvic acid simulated different interference conditions, to construct a four-way data array. After the four-way spectra data is analyzed by AWRCQLD, 4-PARAFAC, and APQLD, three-way EEMs analyzed by APTLD, results show that, on the one hand, PAHs can be measured more accurately with four-way data combined with third-order calibration than lower-order. On the other hand, AWRCQLD algorithm can reflect the superiority of third-order advantage better with higher recovery rate and smaller root mean square error, than other third-order or second-order correction algorithms.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED PHYSICS B-LASERS AND OPTICS
·
2018
·Vol. 125
·期 1
·1-12
·
IF 1.881
Zhang Yiran,Wang Lijun,Liu Peng,Li Youping,Zhan Reggie,Huang Zhen,Lin He
The laser-induced fluorescence technique is widely used in the measurement of polycyclic aromatic hydrocarbons (PAHs) in sooting flames. One of the main limitations is the absence of the PAH fluorescence spectra at elevated temperatures. In this study, fluorescence spectra and photophysical properties of five typical PAHs were experimentally studied in the temperature range of 673–1373 K in an optical cell. The experimental results indicated that the fluorescence spectra of PAHs were greatly sensitive to PAH structures and were likely to shift to the red and became broader as temperature increases. Further, we also observed that absorption cross sections of PAHs increased linearly as a function of temperature. Fluorescence quantum yields, which were calculated using integral fluorescence intensities and absorption cross sections, decreased monotonically with increasing temperature. However, the descent gradients of different PAHs were quite different, e.g., naphthalene, fluoranthene and fluorene were more sensitive to temperature, and their fluorescence production was much lower at elevated temperature compared with phenanthrene and pyrene. In order to investigate the fluorescence quantum yields at higher temperatures (up to 2000 K), which cannot be measured in the optical cell, a multistep decay model was established and optimized based on experimental results. At temperatures between 1373 and 2000 K, the extrapolation results indicated that fluorescence quantum yields of phenanthrene and pyrene would be two orders of magnitude higher than those of naphthalene, fluorene and fluoranthene. This contributed to explaining that the PAH fluorescence signals emitted from phenanthrene and pyrene were stronger than those emitted from naphthalene in flames, although the concentrations of phenanthrene and pyrene were much lower than that of naphthalene in flames.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Guozhi Zhu,Song Shi,Meng Liu,Li Zhao,Min Wang,Xi Zheng,Jin Gao,Jie Xu
Porous solid bases are increasingly attractive for applications in green chemistry and heterogeneous catalysis under relatively mild conditions. Here, covalent triazine frameworks (CTFs) were first applied as a support for the porous solid strong bases through a redox process between the base precursor KNO3 and CTFs, leading to a relatively low calcination temperature (400 °C). As a result, porous organic frameworks possessing ordered microstructures as well as strong basic sites were successfully synthesized. The materials were characterized by X-ray diffraction, Fourier transform infrared, high-resolution transmission electron microscopy, temperature programmed desorption of CO2, and so forth. The obtained solid bases displayed remarkable catalytic activity in the aerobic oxidation of methylene compounds, and the yield of fluorenones could reach 93.6% at 120 °C, which was nearly 3 times higher than that of the control catalyst. The current research may present a new idea for the construction of porous organic polymers with strong basicity.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Songjie Hua,Liang Zhao,Liyuan Cao,Xiaoqin Wang,Jinsen Gao,Chunming Xu
Rapid and selective recognition and adsorption of dibenzothiophene (DBT) was obtained by a novel hollow surface molecular imprinted polymer (SMIP/HCMS), prepared using α-methacrylic acid (MAA) as the functional monomer and porous magnetic carbon microspheres (p-Fe 3 O 4 @C) as the sacrificial support matrix. Some key preparation conditions were systematically optimized. SMIP/HCMS was examined by the characterization of X-ray diffraction, transmission electron microscopy , Fourier transform infrared spectroscopy , N 2 adsorption-desorption isotherms, and thermogravimetric analysis . The adsorption kinetics , adsorption isotherms , selective recognition, and regenerative performance of SMIP/HCMS were also evaluated in detail. The adsorption capacity of SMIP/HCMS for DBT reached 62.06 mg g −1 after 80 min, in comparison with 30.12 mg g −1 of the corresponding non-imprinted polymer and 24.85 mg g −1 of SMIP/p-Fe 3 O 4 @C. In addition, the adsorption kinetics and isotherm data of DBT could be well fitted with the pseudo-first-order kinetic model and Langmuir isotherm, respectively. Competitive adsorption experiments demonstrated that SMIP/HCMS possessed a greater affinity towards DBT than other analogue molecules. Finally, SMIP/HCMS could be used eight times without significant loss in the adsorption capacity. This work indicated the potentiality of SMIP/HCMS, combining using p-Fe 3 O 4 @C as the support matrix with the hollow surface molecular imprinting technology , in the selective removal of DBT from the oil.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2018
·
IF 3.412
Ning Li,Di Wu,Na Hu,Guangsen Fan,Xiuting Li,Jing Sun,Xuefeng Chen,Yourui Suo,Guoliang Li,Yongning Wu
The present study reported a facile, sensitive, and efficient method for enrichment and determination of trace polycyclic aromatic hydrocarbons (PAHs) in food samples by employing new core–shell nanostructure magnetic covalent organic framework hybrid microspheres (Fe3O4@COF-(TpBD)) as the sorbent followed by HPLC-DAD. Under mild synthetic conditions, the Fe3O4@COF-(TpBD) were prepared with the retention of colloidal nanosize, larger specific surface area, higher porosity, uniform morphology, and supermagnetism. The as-prepared materials showed an excellent adsorption ability for PAHs, and the enrichment efficiency of the Fe3O4@COF-(TpBD) could reach 99.95%. The obtained materials also had fast adsorption kinetics and realized adsorption equilibrium within 12 min. The eluent was further analyzed by HPLC-DAD, and good linearity was observed in the range of 1–100 ng/mL with the linear correlation being above 0.9990. The limits of detection (S/N = 3) and limits of quantitation (S/N = 10) for 15 PAHs were in the range of 0.83–11.7 ng/L and 2.76–39.0 ng/L, respectively. For the application, the obtained materials were employed for the enrichment of trace PAHs in food samples and exhibited superior enrichment capacity and excellent applicability.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2012
·
IF 2.237
Wenhua Wang,Yucui Hou,Weize Wu,Muge Niu,Weina Liu
The oxidation of coal to produce high-valued benzene polycarboxylic acids (BPCAs), which are obtained currently from diminishing petroleum reserves, is a promising industrial process of the future. Up to now, the yield distribution of BPCAs has not been studied in detail and the mechanism of coal oxidation to BPCAs remains unclear. In this study, Huolinhe lignite was oxidized in a batch reactor by alkali-oxygen oxidation. All 12 kinds of BPCAs obtained were quantified by a new established method. Effects of alkali/coal mass ratio, reaction temperature, initial oxygen pressure, and reaction time on the yield distribution of BPCAs were studied for the first time. The results indicate that BPCAs with four or five carboxyls are the predominant products, and BPCAs with one or two carboxyls are formed in a relatively short time; moreover, the formation of BPCAs with more carboxyls is relatively more sensitive to the salting out effect. CP/MAS 13C NMR spectra and oxidation of model compounds show that phenolic, ether-substituted aromatic, ether, and aldehyde groups are easily converted and that water-soluble acids (WSA) are formed rapidly and largely due to the breakage of these bonds. The step from WSA to BPCAs is relatively slow mainly due to the inertia of the aromatic clusters with attached carboxyls or carboxylate. On the whole, the BPCAs are derived from aromatic clusters through the oxidation of condensed benzene rings, bridges, or peripheral groups that are attached to the aromatic clusters. Possible mother units for BPCAs in the lignite are suggested based on the generally agreed lignite structure.
✓ 已验证
产品关联
DOI
高影响因子
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.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 4
·683-689
·
IF 2.737
Li Liu,Xin Zhou,Chun Wang,Qiuhua Wu,Zhi Wang
A novel microextraction method, ordered mesoporous carbon reinforced hollow fiber liquid-phase microextraction coupled with high-performance liquid chromatography and fluorescence detection, was developed for the determination of some organic pollutants in water samples. Four polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, and pyrene) were selected to validate this new method. Main parameters that could influence the extraction efficiency such as extraction time, fiber length, stirring rate, the type of the extraction solvent, pH value, the concentration of ordered mesoporous carbon, and salt effect were optimized. Under the optimal extraction conditions, good linearity was observed in the range of 2–1000 ng/L, with the correlation coefficients of 0.9954–0.9986. The recoveries for the spiked samples were in the range of 88.96–100.17%. The limits of detection of the method were 0.4–4 ng/L. The relative standard deviations varied from 4.2–5.9%. The results demonstrated that the newly developed method was an efficient pretreatment and enrichment procedure for the determination of polycyclic aromatic hydrocarbons in environmental water samples.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2015
·
IF 3.545
Qing Wang,Yao Long,Lin Yao,Li Xu,Zhi-Guo Shi,Lanying Xu
A mixed-mode chromatographic stationary phase , C18-DTT (dithiothreitol) silica (SiO 2 ) was prepared through “thiol-ene” click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen , guanine , tetrandrine and nicotinic acid) in the range of 1.82–3.72% and 0.85–1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids , alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons . It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Arabian Journal of Chemistry
·
2015
·
IF 3.725
Chukwunonso Peter Okoli,Gregory Olufemi Adewuyi,Qian Zhang,Guangxu Zhu,Chungyu Wang,Qingjun Guo
Cross linking of starch molecules with suitable reagents provides opportunity for incorporation of relevant functional groups, thereby tuning the adsorption properties of the starch polymer adsorbent towards target pollutants, as a function of the nature of the cross linking agent and the chemical identity of the pollutants. In this vein, this study assessed the applicability of epichlorohydrin cross-linked starch (EPIS), 1,6-hexamethylene diisocyanate cross-linked starch (HDIS), and 4,4-methylene diphenyl diisocyanate cross-linked starch (MDIS) polymer adsorbents for treatment of aqueous Polycyclic Aromatic Hydrocarbon (PAHs) pollution in environmental water samples. Cross-linking process led to improvement in surface characteristics, level of hydrophobicity, and incorporation of relevant functional groups. Adsorption capacities of the adsorbents were in the order of MDIS > HDIS > EPIS. PAHs molecules were adsorbed in multi-layer, in a flat-wise orientation, while external and internal diffusion dominated the adsorption kinetics. Adsorption mechanisms suggested that these adsorbents spontaneously adsorb PAHs molecules driven mainly by enthalpy change, and the adsorption process was attributed to physisorption involving hydrophobic, van der Waals and π–π interactions between adsorbent and adsorbates. The thermodynamic evaluation indicated that the adsorption process was majorly endothermic and spontaneous. Desorption studies indicated that the adsorbents can be efficiently regenerated. The adsorbents were effective in treating simulated and real environmental water samples, and hence, are promising cost-effective alternative for control of aqueous PAHs pollution.
✓ 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）