JOURNAL OF CHROMATOGRAPHY A
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2018
·
IF 3.716
Yixin Yang,Peige Qin,Jing Zhang,Wenqi Li,Jinhua Zhu,Minghua Lu,Zongwei Cai
In this work, a novel nanoscale graphitic carbon nitride hybridized with copper oxide (nano-g-C 3 N 4 /CuO) composite was prepared and used as the coating of solid-phase microextraction (SPME) for the first time. The coating was applied to adsorption and preconcentration of polycyclic aromatic hydrocarbons (PAHs) including naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, and pyrene from water and soil prior to gas chromatography (GC) analysis. Compared with pristine nanoscale graphitic carbon nitride (nano-g-C 3 N 4 ) or copper oxide (CuO), the as-prepared nano-g-C 3 N 4 /CuO composite as the coating of SPME provided the best adsorption affinity for PAHs. Moreover, the extraction efficiencies of the nano-g-C 3 N 4 /CuO coated fibers were much higher than that of bulk-g-C 3 N 4 /CuO hybrids. The developed method exhibited excellent linearity for target analytes in the range of 0.1–1000 ng/mL with determination coefficient (R 2 ) not lower than 0.9944. The limits of detection (LODs) of the established method for the analysis of PAHs were achieved between 0.025 and 0.40 ng/mL. The relative standard deviations (RSDs) for three replicate extractions with one fiber were determined from 2.5% to 7.3%. The fiber-to-fiber reproducibility (n = 3) was 5.4–12.8%. The prepared coating also demonstrated excellent thermal and chemical stability. The method was successfully applied to analysis of target analytes in water and soil samples and the corresponding contents were calculated between 0.07 and 1.58 μg/g.
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CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Yan Zhang,Lu Liu,Peixin Zhang,Jun Wang,Mai Xu,Qiang Deng,Zheling Zeng,Shuguang Deng
Ultra-high surface area and nitrogen-rich porous carbons are prepared via a low-temperature and one-pot N-doping method. The obtained carbons exhibited large surface area of 2965.7 m 2 g −1 and high N-doping level of 6.6 at%, endowing them as efficient gas-mixture selective adsorbents and excellent supercapacitor electrodes. By optimizing the ratio of porogen/carbon or activation temperature, the as-prepared N-rich microporous carbons possessed outstanding mixed-gas selectivities of CO 2 /N 2 (77.9), CO 2 /CH 4 (12.8), and CH 4 /N 2 (4.9) at 298 K and 1 bar. Furthermore, three samples with almost identical surface properties were successfully prepared by judicious selection of activation conditions, thus the favorable effect of pyrrole/pyridine (N-5) species on gas-mixture separation could be clearly demonstrated. Moreover, as supercapacitor electrodes, the N-doped materials displayed extremely high supercapacitance of 350.2 F g −1 at a current density of 0.5 A g −1 in a 6 M KOH electrolyte solution with superior rate retention of 74.2% at 10 A g −1 and 98% capacitance retention after 8000 cycles.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2012
·Vol. 403
·期 3
·877-884
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IF 3.778
Diao Chun-Peng,Wei Chao-Hai
A rapid, sensitive and environmentally friendly method for the analysis of 14 anilines in water samples by dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO) prior to gas chromatography–mass spectrometry (GC-MS) was developed and optimized. In the proposed method, cyclohexane was used as the extraction solvent as its toxicity was much lower than that of the solvent usually used in dispersive liquid–liquid microextraction (DLLME). In the optimized conditions, the method exhibited good analytical performance. Based on a signal-to-noise ratio of 3, limits of detection for anilines were in the range of 0.07 to 0.29 μg L −1 , and the linear range was 0.5–200 μg L −1 with regression coefficients ( r
2 ) higher than 0.9977. It was efficient for qualitative and quantitative analysis of anilines in water samples. The relative standard deviations varied from 2.9 to 8.6 % depending on different compounds indicating good precision. Tap water and river water were selected for evaluating the application to real water samples. The relative recoveries of anilines for the two real samples spiked with 10 μg L −1 anilines were in the scope of 78.2–114.6 % and 77.3–115.6 %, respectively.
Flow diagram of DLLME-SFO
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ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Yu Bing,Zhao Song,Hongtao Jiang,Xiaoyi Xu,Zhongzheng Yu,Tingting Zhou,Tong Zhang
Water competitive adsorption and limited reaction sites on the micro-scale sensing area of micro-electro-mechanical system (MEMS) sensors are two bottleneck problems that restrict the detection of trace indoor polluted gases, leading to drifting and weak signals. To address this, a “duet-insurance” sensing strategy is proposed to protect and amplify the sensing signal. For the first-level protection, the well-designed double-layer structure consisting of Janus TpMa covalent organic framework (COF)/Eu-doped α-Fe 2 O 3 can resist diffusion of water molecules and facilitate the electron transfer from formaldehyde (CH 2 O) to sensing layers, benefiting from the outer hydrophobic character of Janus TpMa and the strong CH 2 O adsorption capacity of Eu-doped Fe 2 O 3 . For the second-level amplification, the unique variable temperature excitation facilitates the deep penetration of CH 2 O into the active sites across COF layers, enabling signal amplification through thermally actuated carrier modulation. The sensor demonstrates high sensing ability to the CH 2 O, with an ultra-low limit of detection of 794 ppt. Leveraging the novel sensing strategy, a multi-functional, visual sensing system is designed to identify multi-indoor pollution gases by feature signal encoding and color mapping, showcasing the promising potential for MEMS sensors based on Janus TpMa COF/Eu-doped α-Fe 2 O 3 materials.
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JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 8
·1388-1393
·
IF 2.737
Yunjian Ma,Cheng Zhao,Yisen Zhan,Jianbin Li,Zhuomin Zhang,Gongke Li
An in situ embedded synthesis strategy was developed for the preparation of a MoO 3 /polypyrrole intercalative sampling adsorbent for the separation and analysis of trace volatile formaldehyde in aquatic products. Structural and morphological characteristics of the MoO 3 /polypyrrole intercalative adsorbent were investigated by a series of characterization methods. The MoO 3 /polypyrrole sampling adsorbent possessed a higher sampling capacity and selectivity for polar formaldehyde than commonly used commercial adsorbent Tenax TA. Finally, the MoO 3 /polypyrrole adsorbent was packed in the thermal desorption tube that was directly coupled to gas chromatography with mass spectrometry for the analysis of trace volatile formaldehyde in aquatic products. Trace volatile formaldehyde from real aquatic products could be selectively sampled and quantified to be 0.43–6.6 mg/kg. The detection limit was achieved as 0.004 μg/L by this method. Good recoveries for spiked aquatic products were achieved in range of 75.0–108% with relative standard deviations of 1.2–9.0%.
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ANALYTICA CHIMICA ACTA
·
2014
·
IF 4.517
Mian Wu,Haibo Zhang,Faqiong Zhao,Baizhao Zeng
A novel poly(3,4-ethylenedioxythiophene)-ionic liquid (i.e., 1-hydroxyethyl-3-methyl imidazolium-bis[(trifluoromethyl)sulfonyl]imide) composite film was electrodeposited on a Pt wire for headspace solid-phase microextraction. The film showed nodular structure and had large specific surface. In addition, it displayed high thermal stability (up to 300 °C) and durable property (could be used for more than 200 times). Coupled with gas chromatography-flame ionization detection, the resulting fiber was applied to the headspace solid-phase microextraction and determination of several alcohols (i.e., linalool, nonanol, terpineol, geraniol, decanol and dodecanol). It presented higher extraction capability in comparison with the poly(3,4-ethylenedioxythiophene) and commercial polydimethylsiloxane/divinylbenzene fiber. Under the optimized conditions, the linear ranges exceeded three magnitudes with correlation coefficients above 0.9952 and the low limits of detection were 34.2–81.3 ng L −1 . For different alcohols the repeatabilities (defined as RSD) were <5.8% and <7.8% for single fiber ( n = 5) and fiber-to-fiber ( n = 4), respectively. The proposed method was applied to the determination of these alcohols in real samples with acceptable recoveries from 81.1% to 106.6%.
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MICROCHEMICAL JOURNAL
·
2015
·
IF 2.746
Na Wang,Ling He,Xiang Zhao,Stefan Simon
The mostly used drying-oils as binding media in historical artworks of eastern tung-oil and western linseed-oil, poppy-oil, walnut-oil are comparatively identified by on-line methylated pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). Based on the analysis of un-pigmented and pigmented reference samples after treated by natural aging, hydro-thermal aging and UV aging, respectively, the characteristic pyrolysis products of all drying-oils are classed into mono-carboxylic acids (C6–8, 14, 16, 18, 20), di-carboxylic acids (2C6–12), glycerol, erythritol , 2-tridecanone, 8-hydroxy-octanoic acid, 3-octyl-oxiraneoctanoic acid and 2,6,10-trimethyl-9-undecenoic acid. Both benzene derivative and 9,10-dihydroxy-octadecanoic acid are suggested as the marked components for distinguishing eastern and western drying-oil. The investigated pigments of malachite, cinnabar, azurite and ochre do not show obvious influence on the detection of characteristic pyrolysis products of drying-oil, but they are proved to accelerate the aging and hydrolyzing rate of drying-oil, especially the pigment of cinnabar. The established on-line methylated Py–GC/MS procedure and the summarized data have been successfully applied on the identification of raw tung-oil and boiled tung-oil in historical painting samples collected from Drum Tower (Ming Dynasty), Bell Tower (Ming Dynasty), and Thousand-Buddha Cliff Grotto (Tang Dynasty). It is believed that the established Py–GC/MS procedure is able to provide wide application in archeological research.
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JOURNAL OF SEPARATION SCIENCE
·
2014
·Vol. 37
·期 12
·1482-1488
·
IF 2.594
Yuling Hu,Zelin Huang,Langjun Zhou,Dongmei Wang,Gongke Li
Nanoscale anatase titania was embedded within the porous chromium terephthalate MIL-101 under low-temperature hydrothermal treatment. The metal–organic framework shell acting as host matrix can effectively prevent the titania nanoparticles from aggregating and enable a good dispersion of these nanoparticles. The X-ray diffraction spectra, transmission electron micrography and X-ray photoelectron spectra clearly showed successful impregnation of the nano-sized anatase titania within the body of MIL-101. The resulting TiO 2 /MIL-101 nanocomposite was considered as bifunctional material with abundant adsorptive domains and catalytic domains, and was packed in a quartz tube as a convenient trapping and photocatalytic reactor for hazardous volatile pollutants. The composite showed great potential for adsorptive and photocatalytic degradation of these volatile pollutants, such as formaldehyde and o -xylene, which were online monitored by thermal desorption gas chromatography with mass spectrometric detection.
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JOURNAL OF CHROMATOGRAPHY A
·
2011
·
IF 4.194
Zhuomin Zhang,Wei Tan,Yuling Hu,Gongke Li
In this paper, an efficient and sensitive analytical method for the simultaneous determination of three trace sterols including ergosterol , stigmasterol and β-sitosterol in complicated biological samples was developed by gas chromatography–mass spectrometry (GC–MS) coupled with extraction using novel β-sitosterol magnetic molecularly imprinted polymer (mag-MIP) beads. Physical tests suggested that β-sitosterol mag-MIP beads prepared by a rapid microwave synthesis method possessed the porous morphology, narrow size distribution, stable chemical and thermal property. Due to the greatly enlarging surface area and the strong recognition to the target molecules, β-sitosterol mag-MIP beads have a higher enrichment factor for β-sitosterol (∼20-fold) and the higher selectivity for β-sitosterol and its analogs than that of β-sitosterol magnetic nonimprinted polymer (mag-NIP) beads. Under the optimum analytical conditions, all the target compounds achieved good chromatographic separation and sensitive detection without matrix interference. It was interesting that three target sterols were actually found in mushroom samples, and stigmasterol and β-sitosterol were actually found in serum and watermelon samples. The recoveries of spiked sample tests were in range of 71.6–88.2% with RSDs of 2.4–10.0% ( n = 3). This method is reliable and applicable for the simultaneous determination of trace sterols in real biological samples based on the β-sitosterol mag-MIP bead extraction.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Linjun Wu,Zhiqiang Shen,Yuexi Zhou,Jiane Zuo
This study rigorously assessed the efficacy of gas-permeable membrane (GPM) technologies in recovering ammonia from landfill leachate, focusing on polypropylene (PP) and expanded polytetrafluoroethylene (ePTFE) membranes within in-situ (INS) and shell-tube (ST) configurations. The research spanned an array of determinants, including influencing factors, sustained operational efficiency, fouling dynamics, and recovery product purity. It was established that the INS-ePTFE configuration demonstrated formidable recovery capabilities and durable performance after fouling cleaning, with ammonia removal efficiency resurging to its initial state and stabilizing at 93 % post-maintenance. In contrast, the ST-PP configuration experienced an unrecoverable drop in removal efficiency to 83 %. Fouling analysis indicated that ePTFE membranes retained structural stability against organic and inorganic deposition, with humic substances and metal carbonates as predominant constituents. Conversely, PP membranes exhibited a decline in hydrophobic properties and structural integrity upon contamination. Furthermore, pH elevation significantly enhanced ammonia nitrogen mass transfer coefficients without increasing osmotic water transfer in INS systems. The INS system also showed promise for synergistic phosphorus recovery within the pH of 9 to 10. Then, NO 3 – , SO 4 2- and humic acid did not impede ammonia translocation, whereas a 1.5 % mass fraction of Ca 2+ incurred a roughly 30 % reduction in ammonia mass transfer coefficients across each system. The recovery of high purity (NH 4 ) 2 SO 4 attested to the exceptional retention capabilities of GPMs for organics and ions, with rejection rates surpassing 99.6 %. The comprehensive analysis underscored the operational superiority of the INS-ePTFE configuration in ammonia recovery.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2025
·
IF 6.2
Huifang Yang,Wenhao Yang,Yuting Zhang,Ramy M. Khoder,Shanbai Xiong,Yueqi An
This study analyzed the changes in key aroma compounds in grass carp fillets during cold storage using aroma extract dilution analysis, odor activity values, and aroma recombination. A total of 11, 13, and 14 volatile compounds were recombined to construct recombination models representing the odor of fillets at 0, 3, and 7 days of cold storage, respectively. The key aroma compounds in fresh fillets included hexanal, (Z)-4-heptenal, nonanal, (E,E)-2,4-octadienal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, (E)-2-decenal, (E,E)-2,4-decadienal, 1-octen-3-ol, and 2,3-pentanedione. Moreover, (E)-2-octenal, 2-cyclopenten-1-one, γ-dodecalactone, and octanoic acid became the key aroma compounds after 3 and 7 days of refrigeration, respectively. (Z)-4-Heptenal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, and (E,E)-2,4-decadienal indicated the deterioration in flavor quality of fillets, which rose by 38.29 μg/kg (0–7 days). This study clarifies the key aroma compounds and characteristic compounds responsible for odor changes during the cold storage of fillets, establishing a basis for future improvement in odor quality during cold storage.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Suqi Liu,Linjiang Pang,Xiaowei Wu,Shihao Chen,Mingyi Yang,Jiyu Cheng,Guoquan Lu,Zhenhe Wang,Wei Chen,Yuge Guan,Xinghua Lu
Changes in the content of trans -caryophyllene could identify whether sweetpotatoes are infected with black spot disease. Therefore, in this study, a quartz crystal microbalance (QCM) sensor based on modified CAU-1@ZIF-8 was used for non-destructive detection of sweetpotato black spot. The experimental results showed that the constructed sensor performed best when both modified CAU-1 and ZIF-8 were present. The sensor showed a linear trend (R 2 = 0.996, limit of detection (LOD) = 0.55 ppm) in response to trans -caryophyllene in the concentration range of 20–340 ppm with a sensitivity of −0.489 Hz (ppm) −1 . The developed gas sensor was successfully used for the detection of trans -caryophyllene in real samples of sweetpotato. The experimental data showed a significant correlation with the results of gas chromatography-mass spectrometry (GC–MS) with a correlation coefficient of 0.970 ( p < 0.01). Therefore, it could be used for early warning of black spot disease in sweetpotato.
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