JOURNAL OF ORGANIC CHEMISTRY
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2018
·
IF 4.805
Jin-Yan Liang,Shou-Jie Shen,Xiao-Qian Chai,Ting Lv
The first Lewis-base-catalyzed unexpected [1 + 2 + 2] annulation reaction between Morita–Baylis–Hillman carbonates and unsaturated pyrazolones was developed. The multicyclic cyclopentane-fused dispiropyrazolone constructions containing five contiguous stereogenic centers, including two spiro quaternary centers, were prepared with excellent yields (81–98%) and moderate to good diastereoselectivities (1:1 to 13:1). Further transformation and gram-scale operations were also achieved efficiently.
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JOURNAL OF CHEMICAL RESEARCH
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2018
·
IF 0.668
Can Jin,Feng Wang,Bin Sun,Xiaohui Zhuang
A novel method for the preparation of N-chloroaldimines from commonly available aromatic aldehydes has been developed. The reaction proceeded effectively by two steps: aldehydes were initially transformed into imines and then chloro-substitution with NaClO2 gave the N-chloroaldimines. This simple protocol allows for the preparation of a variety of aromatic N-chloroaldimines in moderate to excellent yields without the isolation of the imine intermediate. We also found that 3-nitrobenzaldehyde and 4-cyanobenzaldehyde were converted into the related benzonitrile directly under the standard conditions.
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Food Analytical Methods
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2015
·Vol. 9
·期 1
·88-94
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IF 1.956
Jiao Zhe,Jiang Zhibin,Zhang Ni
In this study, copper(II) isonicotinate was first used as an online cleanup adsorbent in selective pressurized liquid extraction (SPLE) for determination of trace residues of polychlorinated biphenyls (PCBs) in fatty food samples. The adsorbent-to-sample ratio, extraction temperature, extraction time, recycle times, etc. were optimized. The PCBs in food samples of pork, chicken meat, and clam meat were detected by gas chromatography–mass spectrometry (GC-MS). The detection limit (S/N = 3) ranged from 0.2 ng/g wet weight (PCB 18) to 2.5 ng/g wet weight (PCB 66). Relative standard deviations (%RSDs) were lower than 12.5 %. The mean recovery was in the range of 82.4–105.1 %. Certified reference materials were analyzed with acceptable results. It was exhibited that the copper(II) isonicotinate showed higher purification capacity than other cleanup adsorbents for extraction of PCBs in fatty food. The proposed method which involved extraction-cleanup in one step can be a promising sample preparation method for food analysis.
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JOURNAL OF SEPARATION SCIENCE
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2014
·Vol. 38
·期 1
·115-120
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IF 2.594
Zhe Jiao,Suling Zhang,Hongwei Chen
For the determination of trace residues of tetracycline antibiotics in fatty food samples, selective pressurized liquid extraction coupled with high-performance liquid chromatography and tandem mass spectrometry was applied in this study. Copper(II) isonicotinate was first used as online cleanup adsorbent in the selective pressurized liquid extraction process. The adsorbent to sample ratio, extraction temperature, extraction time, and recycle times, etc. were optimized. The tetracyclines in food samples of pork, chicken meat, and clam meat were detected by liquid chromatography with tandem mass spectrometry. Tetracycline was found at levels of 0.32 and 0.53 μg/g and oxytetracycline was found at 0.14 and 0.21 μg/g in chicken meat and clam meat, respectively, while chlorotetracycline and deoxytetracycline were below the detection limit. The detection limit (S/N = 3) for these four tetracyclines were from 0.2 to 3.3 ng/g, the recoveries were from 75.8 to 110.5%, and relative standard deviations were from 5.5 to 13.6%. Copper(II) isonicotinate showed a higher purification capacity than other cleanup adsorbents for extraction of antibiotics in fatty food and the recovery showed predominance compared with a pressurized liquid extraction method without adsorbent. The study demonstrated that copper(II) isonicotinate would be a promising cleanup adsorbent in pressurized liquid extraction for the analysis of trace organic pollutants in complicated samples.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2014
·Vol. 131
·期 13
·
IF 1.64
Yang Cao,Lukuan Liu,Wanzhen Xu,Xiangyang Wu,Weihong Huang
The preparation of indole molecularly imprinted polymers (indole-MIPs) using 4-vinylpyridine as functional monomer, silica gel as matrix were used to adsorb indole from fuel oil specifically. The reverse atom transfer radical polymerization (RATRP) technology was introduced to prepare the surface molecularly imprinted polymers, and the precipitation polymerization was adopted in the preparation process. The obtained indole-MIPs were characterized by nitrogen adsorption, Fourier transform infrared spectrometry and scanning electron microscopy. The results show that indole-MIPs were provided with the larger surface areas and more pores. The adsorption capacity of indole-MIPs was 31.80 mg g −1 at 298 K, and the adsorption equilibrium was reached in a short time. The adsorption process was spontaneous by thermodynamic analysis, and an appropriate decrease in temperature could enhance the adsorption capacity. The adsorption process obeyed pseudo-second-order kinetic model by kinetics analysis. The isotherm analysis results show that both Langmuir and Sips equations were suitable to experimental data. The selective adsorption and reusable performance of indole-MIPs were favorable. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40473.
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Catalysis Science & Technology
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2015
·Vol. 6
·期 7
·2403-2412
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IF 5.426
Dong Wang,Yujun Zhu,Chungui Tian,Lei Wang,Wei Zhou,Yongli Dong,Qing Han,Yunfei Liu,Fulong Yuan,Honggang Fu
The introduction of a suitable co-catalyst is a promising way to improve the catalytic efficiency of Pt catalysts. Herein, SBA-15 modified with well-dispersed Mo2N nanoparticles (NPs) is synthesized by anchoring phosphomolybdic acid (HPM) on aminated SBA-15 (SBA-15-NH2) primarily, followed by nitridation treatment under NH3. After loading of Pt, the Pt–Mo2N/SBA-15 catalyst with close-contact Pt and Mo2N NPs can be formed. The intensive interaction of Pt and Mo2N benefited from the close contact is verified by XRD and XPS tests. As a result, the ternary Pt–Mo2N/SBA-15 catalysts have shown superior performance to Pt/SBA-15 catalysts for the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol. The TOF over the 1 wt% Pt–Mo2N/SBA-15 catalyst is close to that over the 3 wt% Pt/SBA-15 catalyst, but its selectivity to cinnamyl alcohol (COL) is 2.5 times that of 3 wt% Pt/SBA-15. The promoted activity of Pt–Mo2N/SBA-15 is mainly attributed to the synergistic effect of Pt and Mo2N NPs, which can cause the full development of the catalytic ability of Pt, thus reducing the Pt usage, through increasing the dispersion of Pt NPs and the fraction of Pt0 species in the catalyst.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2015
·Vol. 22
·期 12
·9224-9232
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IF 2.828
Qin Li,Feng Mingbao,Zhang Xuesheng,Wang Liansheng,Wang Zunyao
Polychlorinated diphenyl ethers (PCDEs) are a group of halogenated aromatic compounds and serious environmental pollutants. In the present study, sediment and water samples from eight sites in Nanjing section of the Yangtze River were characterized with 15 congeners of PCDEs. Concentrations and distributions of these PCDEs in water phase and sediments were analyzed by GC/MS. Results demonstrated that ∑PCDE concentrations were higher in the low water period (1.15–1.80 μg/L) than those in the high water period (0.73–1.30 μg/L) in water phase. Moreover, ∑PCDE concentrations were higher in the low water period (1.58–3.98 μg/kg) than those in the high water period (1.24–3.48 μg/kg) in sediments. A significant linear relationship existed between the ∑PCDE concentrations and TOC contents in sediments, but a poor linearity was found between ∑PCDE concentrations and DOC contents in water phase. Furthermore, the comparison of the percentage compositions in sediments and in water phase showed that CDE-30 (2,4,6-tri-CDE) was the predominant congener in the studied sites, and higher chlorinated congeners accounted for a larger proportion in sediments than those in water phase. In conclusion, the present study demonstrated the prevalent contamination by PCDEs in sediments and water from the Nanjing section of the Yangtze River.
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ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2015
·Vol. 69
·期 4
·453-460
·
IF 1.895
He Qun,Qin Li,Zhang Xuesheng,Wang Liansheng,Sun Ping,Wang Zunyao
Sediment and water samples collected from 8 sites of the Yangtze River in Nanjing section were characterized with 31 congeners of polychlorodibenzothiophenes (PCDTs). Concentrations and percentage compositions of these PCDTs in water and sediments were analyzed by gas chromatography–mass spectrometry. Results showed that ∑PCDT concentrations in sediments were higher (0.86–1.75 μg/kg) than those in water (0.56–1.30 μg/L). A linear relationship existed between ∑PCDT concentrations and total organic carbon content in sediments, whereas there was a poor linearity between ∑PCDTs concentrations and dissolved organic carbon content in water phase. Moreover, percentage compositions showed that penta-chlorinated DTs were the predominant congeners both in sediments and water. Differences existed in the percentage compositions between water and sediments. Highly chlorinated DTs accounted for a larger proportion in sediments than those in water. In conclusion, the present study showed the prevalent contamination by PCDTs in sediments and water from the Nanjing section of the Yangtze River.
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ANALYST
·
2015
·Vol. 140
·期 17
·5944-5952
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IF 4.107
Shaoyan Zhou,Zheng Li,Xueju Lv,Bin Hu,Qiong Jia
Here, we synthesized a novel organic–inorganic hybrid material combining carboxylatocalix[4]arenes and magnetic zeolites by covalent bonding. The complex was characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transformed infrared spectroscopy, X-ray diffraction spectrometry, thermogravimetric analysis/differential thermal gravity analysis, and by using an X-ray photoelectron spectrometer and a vibrating sample magnetometer. The resulting magnetic composite was employed as a solid phase adsorbent to separate and preconcentrate synthetic phenolic antioxidants. Various interactions between the targets and the adsorbent contributed to the adsorption efficiency including hydrophobic interaction, hydrogen-bond interaction, and π–π complexation. The superparamagnetic participation in the process of synthesizing zeolites made the separation process of adsorbent from solutions convenient by an external magnetic field. Taking advantage of this property, this adsorbent could be recycled more than 30 times. The concentrations of the preconcentrated SPAs were determined directly by high-performance liquid chromatography. Various experimental parameters were optimized, according to which the method was evaluated. Finally, the prepared magnetic zeolite@carboxylatocalix[4]arene was successfully applied to identify synthetic phenolic antioxidants from juice and infant milk powder samples with high enrichment factors in the range of 41.9–92.5. The magnetic materials allowed rapid and simple preconcentration, implying their potential in the field of adsorption.
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Analytical Methods
·
2014
·Vol. 6
·期 17
·6651-6657
·
IF 1.938
Zhiyong Zhao,Suquan Song,Na Liu,Qinxiong Rao,Jiafa Hou,Sarah De Saeger,Aibo Wu
Food safety monitoring and toxicological research of mycotoxins are still in need of large quantities of high-purity deoxynivalenol (DON). To attain this purpose, a rapid, economical and reproducible purification method was developed for large-scale production of DON from rice culture inoculated with a DON-producing Fusarium graminearum strain JYH. The inoculated rice culture was first extracted with acetonitrile–water (84/16, v/v). The extracts were evaporated to dryness on a rotary evaporator after ethyl acetate partitioning and then dissolved in water followed by the final purification procedure through preparative high performance liquid chromatography and montmorillonite treatment. A combined approach of ultraviolet spectrometry (UV), ultra high performance liquid chromatography (UHPLC), mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy was applied for the multi-dimensional characterization of the target compound. As a result, the recovery of DON from the crude extract to the final product was up to 70%. An amount of 150 mg DON with the desirable purity of 98.93% could be obtained from 100 g of rice culture, which possessed identical immunochemical characteristics compared to a certified commercial DON standard. This proposed strategy might act as a valuable reference to obtain rather expensive compounds in a straightforward way.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2015
·
IF 2.729
Xiaolan Zeng,Xuesheng Zhang,Li Qin,Zunyao Wang
The tissue distribution, excretion, and metabolic pathway of 2,2′,4,4′,5-penta-chlorinated diphenylsulfide (CDPS-99) in ICR mice were investigated after oral perfusion at 10 mg/kg body weight (b.w.). Biological samples were extracted and separated and, for the first time, were determined by a novel, sensitive, and specific GC–MS method under the full scan and selected ion monitoring (SIM) modes. The results showed that the concentrations of CDPS-99 in the liver, kidneys, and serum reached a maximum after a one-day exposure and that the CDPS-99 concentration in the liver was the highest (3.43 μg/g). The increase in the concentration of CDPS-99 in muscle, skin, and adipose tissue was slower, and the concentrations of CDPS-99 achieved their highest levels after 3 days of exposure. It was observed that the CDPS-99 concentration in adipose tissue was still very high (0.71 μg/g) after 21 days of exposure, which suggested that CDPS-99 was able to accumulate in adipose tissue. In addition, mouse feces accounted for approximately 75% of the total gavage dose, indicating that CDPS-99 was mainly excreted via mouse feces. Metabolism analysis demonstrated that there were three possible metabolic pathways of CDPS-99 in mice: dechlorination reactions with the formation of tetra-CDPS and hydroxylation and oxidation reactions with the formation of OH-CDPS-99 and chlorinated diphenylsulfone. The present study will help to develop a better understanding of mammalian metabolism of CDPS-99.
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TETRAHEDRON
·
2015
·
IF 2.641
Xingzhu Xu,Haibo Wu,Zhengyi Li,Xiaoqiang Sun,Zhiming Wang
The development of bimetallic iron oxide-silver magnetic nanoparticles (Fe 2 O 3 –Ag MNPs) catalytic system provides an efficient heterogeneous synthetic pathway to allylic amines and 1,2-dihydroquinolines involving the direct inter/intramolecular nucleophilic substitution of π-activated alcohols with electron-deficient amines. The major advantages of the present method are wide substrate scope, simple product separation, low catalyst loading, and magnetically recyclable catalyst.
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