JOURNAL OF SEPARATION SCIENCE
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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 Materials Chemistry A
·
2014
·Vol. 3
·期 2
·600-607
·
IF 0
Hanxing Chen,Ming Wen,Zaidi Huang,Qingsheng Wu,Jiali Liu,Teng Tu
Highly active Cu@ZnO brush-like nanostructures have been successfully synthesized through the heteroepitaxial growth process of ZnO branched nanorods (NRs) based on Cu core nanowires (NWs), and used for the evaluation of selective catalytic degradation for polycyclic aromatic compounds. The resultant Cu@ZnO nanobrushes, with the main diameter of ∼500 nm, consist of Cu core NWs with diameter of ∼50 nm and outer ZnO branch NRs shells with thickness of ∼250 nm. The as-designed Cu@ZnO nanobrushes exhibit high performance for the selective catalytic degradation of polycyclic aromatic compounds. Nearly 90% conversion with the reaction rate constant (k) of 0.012 min−1 can be achieved for anthracene, while only about 50% and 10% conversions are shown for phenanthrene and naphthalene, respectively. Besides the highly efficient transportation of electrons, Cu NWs have strong capacity for oxygen activation which results in the gathering of negative charges and rich chemisorbed oxygen onto the surface, which is responsible for the high catalytic efficiency of Cu@ZnO nanobrushes toward the selective degradation of anthracene.
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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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ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Hao Li,Leyu Wang
A facile method is presented for the selective luminescence detection of trace polycyclic aromatic hydrocarbons (PAHs) based on a combination of the specific recognition of molecularly imprinted polymers (MIPs) and magnetic separation (MS). Multifunctional magnetic–luminescent MIP nanocomposites were fabricated via a one-pot emulsion strategy using polystyrene-co-methacrylic acid copolymer, hydrophobic Fe3O4 nanoparticles and luminescent LaVO4:Eu3+ nanoparticles as building blocks with a phenanthrene template. The resulting nanocomposites can be employed in a simple method for the luminescence detection of phenanthrene. Furthermore, magnetic separation of the nanocomposites from the target mixture prior to luminescence detection of phenanthrene affords significantly enhanced selectivity and sensitivity, with a 3σ limit of detection (LOD) as low as 3.64 ng/mL. Milk samples spiked with phenanthrene (5.0 μg/mL) were assayed via this method and recoveries ranging from 97.11 to 101.9% were obtained, showing that our strategy is potentially applicable for the preconcentration, recovering, and monitoring of trace PAHs in complex mixtures.
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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.
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JOURNAL OF CHROMATOGRAPHY A
·
2013
·
IF 4.612
Xingmei Guan,Chuande Zhao,Xiaoyan Liu,Haixia Zhang
A polymer monolith column was prepared using click chemistry for on-line solid phase microextraction of polycyclic aromatic hydrocarbons (PAHs), using 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene(TES) and 1,4-bis(6-azidoalkoxy)benzene (BAB) as monomers, and Cu(PPh 3 ) 3 Br as the catalyst. The polymer with spirocyclic cross-links was porous and presented an appropriate interspace of PAHs. Enrichment of PAHs, in the range of 100 to more than 1000 times, was due to the π – π stacking interaction and the effect of small size. The factors affecting the on-line microextraction efficiency were optimized, and the analytical conditions were evaluated to ensure reliability.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Xingru Hu,Chao Liu,Jiansheng Li,Rui Luo,Hui Jiang,Xiuyun Sun,Jinyou Shen,Weiqing Han,Lianjun Wang
In this study, a novel hollow mesoporous carbon spheres-based fiber (HMCSs-F) was fabricated to immobilize HMCSs onto a stainless steel wire for solid-phase microextraction (SPME). Characterization results showed that the HMCSs-F possessed a large specific surface area, high porosity and uniform pore size. To demonstrate the extraction performance, a series of polycyclic aromatic hydrocarbons (PAHs) was chosen as target analytes. The experimental parameters including extraction and desorption conditions were optimized. Compared to commercial fibers, the HMCSs-F exhibited better extraction efficiency for PAHs. More interestingly, a good extraction selectivity for PAHs from the complex matrix was observed in these HMCSs-F. The enhanced SPME performance was attributed to the unique pore structure and special surface properties of the HMCSs. Furthermore, under the optimum conditions, the limits of detection (LODs) for the HMCSs-F were in the range of 0.20–1.15 ng L −1 with a corresponding relative standard deviation that was below 8.6%. The method was successfully applied for the analysis of PAHs in actual environmental water samples with recoveries ranging from 85.9% to 112.2%. These results imply that the novel HMCSs-F have potential application in environmental water analysis.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Juanjuan Wu,Ruiyang Ma,Lin Hao,Chun Wang,Qiuhua Wu,Zhi Wang
A hypercrosslinked organic polymer material (named as PPTPA) was prepared by a simple one-step self-polycondensation of triphenylamine. A series of characterization experiments, including N 2 adsorption, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, and thermogravimetric analysis, were carried out to evaluate the morphology, structure and other intrinsic properties of the PPTPA. To investigate its adsorption performance, the PPTPA was used as the solid-phase extraction adsorbent for the extraction of phenylurea herbicides from water, milk and tomato juice samples followed by high-performance liquid chromatographic analysis. Under optimum conditions, good linearity for the analytes was observed in the range of 0.05–40.0 ng mL −1 , 0.1-40.0 ng mL −1 and 0.5–40.0 ng mL −1 for water, milk and tomato juice samples, respectively. The established method also showed low limits of detection (S/N = 3) in the range of 0.008–0.01 ng mL −1 , 0.01–0.03 ng mL −1 and 0.05–0.1 ng mL −1 for water, milk and tomato juice samples, respectively. The possible adsorption mechanism of the PPTPA towards the analytes was investigated, and the results demonstrated that the hydrogen bonding was the main interaction force between the PPTPA and the analytes. It suggests that the PPTPA can serve as a promisingadsorbent for the efficient pre-enrichment of organic compounds with more hydrogen-bonding donor sites.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Chengjiang Zhang,Xialin Luo,Tianfu Wei,Yufei Hu,Gongke Li,Zhuomin Zhang
A new dynamic covalent polymer (DCP) gel was well designed and constructed based on imine chemistry. Polycondensation of 4,4′-biphenyldicarboxaldehyde and 1,3,5-benzenetricarbohydrazide via Schiff-base reaction resulted in an acylhydrazone bond gel (AB-gel) DCP. AB-gel DCP had three-dimensional network of interconnected nanoparticles with hierarchically porous structure. AB-gel DCP was successfully fabricated as a monolithic column by an in-situ chemical bonding method for online enrichment and separation purpose with excellent permeability. AB-gel DCP based monolithic column showed remarkable adsorption affinity towards target analytes including sulfonamides (SAs) and fluorescent whitening agents (FWAs) due to its strong π-π affinity, hydrophobic effect and hydrogen bonding interaction. Then, AB-gel DCP based monolithic column was applied for online separation and analysis of trace SAs and FWAs in food samples coupled with high-performance liquid chromatography (HPLC). Sulfathiazole (ST) and sulfadimidine (SM2) in one positive weever sample were actually found and determined with concentrations of 273.8 and 286.3 μg/kg, respectively. 2,5-Bis(5- tert -butyl-2-benzoxazolyl) thiophene (FWA184) was actually quantified in one tea infusion sample with the concentration of 268.5 ng/L. The spiked experiments suggested the good recoveries in range of 74.5–110% for SAs in weever and shrimp samples with relative standard deviations (RSDs) less than 9.7% and in range of 74.0-113% for FWAs in milk and tea infusion samples with RSDs less than 9.0%. AB-gel DCP monolithic column was proved to be a promising sample preparation medium for online separation and analysis of trace analytes in food samples with complex matrices.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 10
·3773-3779
·
IF 4.58
Wu Juanjuan,Liang Xinyu,Hao Lin,Wang Chun,Wu Qiuhua,Wang Zhi
A nanocomposite (designated as PAG) possessing amphiphilic properties was prepared by a single-step method from graphene oxide and phytic acid, in which phytic acid acts as both an inducer and cross-linking agent. The morphology and microstructure of PAG were characterized by nitrogen adsorption, scanning electron microscopy and transmission electron microscopy. The PAG possess a 3 dimensional network structure with interpenetrated nano- and micropores and represent a viable adsorbent for solid-phase extraction of carbamate pesticides prior to their quantitation by high performance liquid chromatography. Under optimum conditions, the calibration plot is linear in the 0.5 to 80 ng g −1 concentration range in case of apple samples, and in the 1.0 to 80 ng mL −1 range for juice samples. The respective limits of detection (for S / N = 3) are between 0.05 and 0.1 ng g −1 , and between 0.2 and 0.3 ng mL −1 . The PAG has a high adsorption capability, and in our preception it may become a useful adsorbent for the preconcentration of other organic pollutants.
A amphiphilic nanocomposite (prepared from phytic acid and graphene oxide; denoted as PAG) was prepared by a single-step method. Phytic acid acts as both an inducer and cross-linking agent. The PAG was used as an adsorbent to extract carbamates from apple and juice samples.
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JOURNAL OF MOLECULAR STRUCTURE
·
2016
·
IF 1.78
Jingdan Wang,Anqi He,Ran Guo,Yongju Wei,Juan Feng,Yizhuang Xu,Isao Noda,Jinguang Wu
Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane . When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.
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JOURNAL OF APPLIED MICROBIOLOGY
·
2016
·Vol. 121
·期 6
·1616-1626
·
IF 2.156
Huang X.,Shi J.,Cui C.,Yin H.,Zhang R.,Ma X.,Zhang X.
AimsWe aimed to investigate the phenanthrene degradation characteristics and possible phenanthrene degradation pathways of Rhizobium petrolearium SL‐1.Methods and ResultsUsing high‐performance liquid chromatography (HPLC), UV‐visible and gas chromatography‐mass spectrometry (GC‐MS) analysis, the phenanthrene‐degrading properties and metabolites of Rh. petrolearium SL‐1 were analysed, and then combined with genome‐based analysis to elucidate the possible biodegradation pathway of phenanthrene in Rh. petrolearium SL‐1. The results of the analyses showed that phenanthrene (100 mg l−1) was completely degraded by strain SL‐1 at 35°C, 0·02% salinity and pH 9·0 within 3 days. A wide range of polycyclic aromatic hydrocarbons, including naphthalene, fluorene, anthracene and pyrene, could also be degraded by this strain.ConclusionsBased on the identified metabolites, the utilization of probable intermediates and the presence of putative phenanthrene catabolic genes, we concluded that phenanthrene was degraded via two different routes, namely the ‘naphthalene’ and the ‘phthalic acid’ routes.Significance and Impact of the StudyFor the first time, this study shows the degradation pathway of phenanthrene by a Rhizobium strain. Because of its excellent stress resistance, metabolic versatility, high degradation efficiency and potential application in phytoremediation, Rh. petrolearium SL‐1 is a potential candidate for the bioremediation of polycyclic aromatic hydrocarbons‐contaminated areas.
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