JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Xue Xiong,Meiling Qi
This work describes the separation performance of utilizing hexagonal boron nitride (h-BN) as the stationary phase for capillary gas chromatography (GC). The statically coated h-BN column showed moderate polarity and achieved column efficiencies of 3455 plates/m and 3800 plates/m for naphthalene and n -dodecane, respectively. With temperature-dependent structure properties, the h-BN stationary phase exhibited stronger retention for polycyclic aromatic hydrocarbons (PAHs) over phthalic acid esters (PAEs) and showed advantageous separation performance over the g-C 3 N 4 and commercial polysiloxane stationary phases. Moreover, it displayed preferential retention for halogenated analytes and high resolution performance for structural and positional isomers. In addition, the h-BN column showed good column repeatability with relative standard deviation (RSD) values of 0.03%–0.07% for run-to-run, 0.31%–0.71% for day-to-day and 2.6%–5.3% for column-to-column, respectively, and thermal stability up to 260 °C.
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JOURNAL OF CHROMATOGRAPHY A
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2018
·
IF 3.716
Qing Liu,Kevin Yan,Qiaomei Chen,Soumia Cheddah,Lin Shen,Han Xiao,Yan Wang,Chao Yan
Capillary column packed with silica colloidal crystals (SCC) exhibits great efficiency in liquid chromatography because of its highly-ordered structure and extremely narrow channels (about hundred nanometer in diameter) between the particles. However, problems arise due to the extremely high back-pressure created with its dense packings. It is also a challenge to prepare a stable SCC column with an appropriate length for chromatographic separation on a commercial instrument. We have synthesized monodispersed, sub-micron SiO 2 particles bonded with C18 functionality and fabricated SCC capillary columns up to 100 mm in length. The packing materials in the column displayed Bragg diffraction with blueish color under irradiation with white light, indicating the formation of SCC. The column performance was evaluated using pressurized capillary electrochromatography (pCEC) and column efficiencies of more than a hundred thousand plates per column (plate height < 1 μm) were achieved using peptide as a sample. The run-to-run reproducibility expressed with RSD in terms of retention time and peak area for aromatic compounds were less than 0.076% and 1.96%, respectively. These results demonstrate that the combination of pCEC and SCC columns may provide an innovative analytical technique with extraordinary efficiency, resolution and speed for the separation of complex samples.
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JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Jing Li,Li Xu,Zhi-guo Shi
In this study, the ethyl-bridged hybrid silica microsphere with hierarchically meso-macroporous structure was initially synthesized through a method combining dispersion polymerization with sol-gel transition and phase separation. The flow-through macropores rendered the microsphere a rough surface like a waxberry, and thus the material was named as waxberry-like ethyl-bridged hybrid silica sphere (WEHS). WEHS was characteristic of appropriate alkali-stability, which was highly difficult for the pure silica. Additionally, WEHS possessed hierarchical meso- and macropores, which added additional value for faster mass transfer than the conventional fully porous silica materials. Taking the advantages of WEHS, it was successfully applied as the substrate to immobilize lipase; the prepared immobilized lipase exhibited high catalytic activity and favorable reusability under alkaline conditions, which was significant in pitch control of neutral-alkaline papermaking industry. Moreover, as the high-performance liquid chromatographic stationary phase matrix, WEHS made the separation under alkaline mobile phase into a reality for the silica-based materials. Besides, an ultra-fast and efficient separation in minutes was achieved with lower consumption of solvents and saving analytical time, which is highly desired in modern analysis. In general, WEHS was a novel and promising candidate in the myriads of silica-based materials.
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ANALYTICA CHIMICA ACTA
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2015
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IF 4.513
Juan Zheng,Kun Wang,Erlun Luo,Dingcai Wu,Fang Zhu,Ruifen Jiang,Chengyong Su,Chaohai Wei,Gangfeng Ouyang
The monodisperse microporous carbon nanospheres (MMCNSs) were applied in solid phase microextraction for the first time. The MMCNSs-fiber was prepared by sol–gel technique and good repeatability and reproducibility were obtained, due to the excellent monodispersity of the MMCNSs . The sol–gel-MMCNSs fiber exhibited superior extraction ability for polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), compared with the commercial polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber and the fiber prepared with its precursor, the monodisperse microporous polystyrene nanospheres (MMPNSs). Moreover, the fiber has good thermostability and strong acid/base durability. The sol–gel-MMCNSs fiber was then employed to detect PAHs and OCPs in aqueous samples by combining with gas chromatography–mass spectrometer (GC–MS). Under the optimized conditions, the detection limits of the proposed method ranged from 0.10 to 5.5 ng L −1 . Furthermore, the method was successfully utilized for the analysis of PAHs and OCPs in real samples, with satisfactory recoveries in the range of 81.0–120% for the Pearl River water samples and 72.8–118% for the coking wastewater samples.
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JOURNAL OF CHROMATOGRAPHY A
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2016
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IF 3.926
Li-Hua Liu,Cheng-Xiong Yang,Xiu-Ping Yan
Covalent-organic frameworks (COFs) are a newfangled class of intriguing microporous materials. Considering their unique properties, COFs should be promising as packing materials for high performance liquid chromatography (HPLC). However, the irregular shape and sub-micrometer size of COFs synthesized via the traditional methods render the main obstacles for the application of COFs in HPLC. Herein, we report the preparation of methacrylate-bonded COF monolithic columns for HPLC to overcome the above obstacles. The prepared COF bonded monolithic columns not only show good homogeneity and permeability, but also give high column efficiency, good resolution and precision for HPLC separation of small molecules including polycyclic aromatic hydrocarbons, phenols, anilines, nonsteroidal anti-inflammatory drugs and benzothiophenes. Compared with the bare polymer monolithic column, the COF bonded monolithic columns show enhanced hydrophobic, π-π and hydrogen bond interactions in reverse phase HPLC. The results reveal the great potential of COF bonded monoliths for HPLC and COFs in separation sciences.
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JOURNAL OF CHROMATOGRAPHY A
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2015
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IF 4.169
Shu-Wen Xue,Min-Qiong Tang,Li Xu,Zhi-guo Shi
Magnetic nanoparticles (MNPs) featured with divinylbenzene (DVB) and sulfonate functionalities (Fe 3 O 4 –DVB–SO 3 − ) were prepared via “thiol-ene” click chemistry. The hydrophobic DVB moieties were dedicated for extraction while the hydrophilic sulfonate groups were designed for dispersing the MNPs in aqueous sample solution. Thus, the specially designed material could ensure operational convenience and improve reproducibility during extraction. The application of the material was demonstrated by the extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples followed by gas chromatography–mass spectrometric analysis. The main factors influencing the extraction, including the type of the desorption solvent, the agitation mode, the amount of MNPs, extraction and desorption time and salt addition in sample solution, were investigated in detail. Under the optimized conditions, the proposed method showed satisfactory reproducibility with intra-day and inter-day relative standard deviations less than 16.5% and 21.2%, and low limits of detection of 1.1 pg mL −1 , 0.8 pg mL −1 , 1.1 pg mL −1 , 1.4 pg mL −1 , 0.6 pg mL −1 , 2.1 pg mL −1 and 0.7 pg mL −1 for naphthalene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene and pyrene, respectively. The developed method was also successfully used for determination of the PAHs in genuine lake and river environmental water samples by standard addition method. All the studied PAHs were detected in these waters with comparable results by the standard liquid–liquid extraction method. The developed MNPs with dual property of hydrophobicity and hydrophilicity were suitable for the treatment of water samples. The magnetic solid phase extraction based on this material was reliable and convenient. It has great potential in the preconcentration of trace analytes in complex matrix.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 18
·4073-4084
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IF 3.286
Xia Ling,He Yuanyuan,Xiao Xiaohua,Li Gongke
Herein, a total online device based on field-assisted extraction (FAE), micro-solid-phase extraction (μ-SPE), and high-performance liquid chromatography (HPLC) was designed. Solid samples were pretreated with ultrasound-microwave synergic effects, and then the extract was cleaned up online with a monolithic column, followed by HPLC analysis. The cross-actions between ultrasound and microwave along with other extraction parameters were studied systematically. The efficiency of this online method was verified in the determination of polycyclic aromatic hydrocarbons (PAHs) in foods and tetracycline antibiotics (TCAs) in cosmetic samples. The detection limits of nine PAHs including fluorene, phenanthrene, anthracene, fluoranthene, benzo[k]fluoranthene, benz[a]anthracene, benzo[b]fluoranthene, pyrene, and benzo[a]pyrene were all within 0.075–0.30 μg/kg, as well as four TCAs including oxytetracycline, tetracycline, chlortetracycline, and doxycycline were within 0.02–0.06 μg/kg. Six PAHs were found in roast potatoes and baked fish and the recoveries were in the range of 71.5–119.7% with RSDs of 0.2–10.9% ( n = 3). The recoveries for TCAs in cosmetic samples were in the range of 75.3–118.0% with RSDs lower than 8.2% ( n = 3). Compared with those offline methods, this total online FAE-μ-SPE-HPLC method not only simplifies the operation process, but also increases the precision and accuracy. Beyond trace analytes analysis in solid and semi-solid matrixes, application of this total online analysis method can also be extended to investigate field-assisted extraction mechanisms.
Graphical abstract
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Journal of Environmental Chemical Engineering
·
2025
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IF 7.2
Guangyu Dong,Liushan Jiang,Linchun Nie,Jiawei Liao,Xiaodie Geng,Wenjing Liu,Dejing Meng,Meiling Xu,Na Liu,Qingxiang Zhou,Chunmao Chen
In this study, a magnetic covalent organic framework composite (Fe 3 O 4 @COF-BTCA-TMB) was conceived and synthesized with benzene-1,3,5-tricarbaldehyde and 3,3’,5,5’-tetramethyl benzidine as monomers. The modification of COF endowed the magnetic composite with a large number of functional groups and benzene rings, which exhibited high affinity to polycyclic aromatic hydrocarbons (PAHs) attributed to π-π conjugation and hydrophobic interaction. Based on these properties, it was utilized to conceive a highly efficient magnetic solid phase extraction method to enrich PAHs from water samples prior to high performance liquid chromatography analysis. The key factors that affect the extraction efficiencies of six PAHs in water samples were explored. Under the optimized conditions, six PAHs obtained good linearity in wide concentration ranges of 0.2–80 μg L −1 , 0.2–180 μg L −1 , and 0.2–240 μg L −1 , respectively. The limits of detection (LODs) ranged from 0.03 to 0.09 μg L −1 , and the enrichment factors were in the range of 107–149. The adsorption of PAHs on Fe 3 O 4 @COF was consistent with the quasi-second-order kinetic model, and Freundlich adsorption isotherm model. The conceived method was evaluated with real water samples and satisfactory recoveries (73.8 % ∼ 100.5 %) were obtained, indicating that it was simple, robust and efficient, and could be optioned for monitoring trace PAHs in environment.
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Toxics
·
2024
·Vol. 12
·期 11
·796
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IF 3.9
Xintong Li,Baocheng Qu,Jingyao Wang,Hongxia Zhao
Environmentally persistent free radicals (EPFRs) generated on particles under irradiation in water have attracted particular attention, and their formation mechanisms are not well understood. This study investigated the photoformation of EPFRs on both actual samples collected from an oil production plant in Panjin, Liaoning, China, and simulated Fe(III)-montmorillonite samples in water. The EPFRs detected on actual samples were not easily generated compared with those in the soil or in the air, based on the concentrations of identified PAHs. EPR signals in the range of 1017to 1018spin/g were detected on the simulated Fe(III)-montmorillonite samples. Their g factors were smaller than 2.0030, which indicated the generation of carbon-centered EPFRs. The primary byproducts were identified by chromatography–mass spectrometry (GC-MS), and a possible EPFR formation pathway during PAH degradation was proposed. Hydrogenation of PAHs during the photoformation of EPFRs was observed and might be due to the catalysis of the simulated particles and the interaction of the intermediates. Meanwhile, the effects of the typical anions (NO2−and Cl−) and the surfactant (TWEEN®80 and sodium dodecyl sulfate) were investigated and indicated that the phototransformation process and adsorption process would affect the formation of EPFRs. Overall, our study provided useful information to understand the photoformation of EPFRs in aqueous environments.
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DYES AND PIGMENTS
·
2025
·
IF 4.2
Song Liu,Henggang Wang,Dongbo Chen,Chenglong Ji,Zhenguang Wang
Developing efficient, long-lasting room-temperature phosphorescence (RTP) materials via a simple synthesis strategy remains highly desirable yet challenging. Herein, we report a melt-injection reaction for the synthesis of RTP materials, wherein guest molecules and paraformaldehyde are injected into molten urea. Strikingly, this approach transforms the originally weak emission of guest molecules into RTP materials with a photoluminescence quantum yield of 76 % and an emission lifetime of 4.6 s. The efficient and long-lived RTP are attributed to a matrix stabilization mechanism: upon injecting formaldehyde into molten urea, a urea-formaldehyde (UF) matrix forms in situ, concomitantly incorporating guest molecules. Hydrogen bonding between the UF matrix and guest molecules drives the formation of cross-linking networks, which not only narrow the energy gap between singlet and triplet states but also restrict guest molecular motion. Furthermore, the rigid UF matrix shields triplet excitons from quenching by oxygen and water, synergistically enhancing RTP performance. As a proof-of-concept application, these RTP materials were employed as photo conversion layers to fabricate information encryption devices. This study provides new insights into RTP material design and highlights their promising potential in information security, chemical sensing, and bio-imaging.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
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2025
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IF 4.6
Peipei Zhou,Qi Jing,Huili Wang,Xuedong Wang,He Mei
Increasing polycyclic aromatic hydrocarbons (PAHs) pollution in dietary is becoming a significant worldwide problem due to their direct threat to human health. To achieve rapid and sensitive detection of PAHs, nanocomposites were fabricated by confining ionic liquids (ILs) within magnetic covalent organic frameworks (MCOFs). After the confinement of [C 8 MIM][PF 6 ] into MCOFs, the resulting MCOF@8 C maintained high crystallinity comparable to that of the pristine MCOF, limited the diffusion of ILs and reduced the aggregation effect caused by their high viscosity. The MCOF@8 C/HPLC-FLD method gave low detection limits (0.01-0.15 µg kg -1 ), good recoveries (85.32-99.57%) with RSDs ≤ 5.03% for seven PAHs congeners across five types of edible oils. In general, this study not only provides an excellent substitute for conventional multifunctional composites, but also develops a superior methodology for monitoring trace-level PAHs in complicated food matrices.
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