JOURNAL OF SEPARATION SCIENCE
·
2016
·Vol. 39
·期 10
·1926-1934
·
IF 2.741
Chun-peng Diao,Xiaoting Yu,Cong Li,Xiao Yang,Aling Sun,Renmin Liu
A vortex-assisted magnetic matrix solid-phase dispersion method was proposed for the determination of polychlorinated biphenyls in different matrix water samples by gas chromatography with electron capture detection. Magnetic bamboo charcoal (MBC) was synthesized for the adsorption of polychlorinated biphenyls in water samples. Complete separation of the liquid phase and the solid magnetic bamboo charcoal was easily achieved by using a permanent magnet. Under the optimized conditions, good linearity in the range of 0.006–5.0 μg/L was obtained with regression coefficients ( r ) higher than 0.9986. Based on a signal-to-noise ratio of 3, limits of detection were found to be 0.001–0.003 μg/L. Relative standard deviations ranged from 2.92 to 6.56%. Relative recoveries were 96.6–111.2% for the spiked wastewater sample and 90.7–104.7% for the spiked lake water sample. All results showed that the proposed method was simple, sensitive, and reliable for the determination of polychlorinated biphenyls in water samples.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Yin Zhu,Hai-Peng Lv,Wei-Dong Dai,Li Guo,Jun-Feng Tan,Yue Zhang,Fang-Lin Yu,Chen-Yang Shao,Qun-Hua Peng,Zhi Lin
Aroma is one of the most important determinants of tea quality; thus, the precise characterization of the chemical composition of tea aroma is of significant value. In this study, aroma components of the most famous Chinese green tea, Xihu Longjing tea, were first systematically analyzed using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) combined with simultaneous distillation extraction (SDE). 478 volatile compounds were identified as common constituents of fifty-five Xihu Longjing tea samples based on standard mass spectra in available databases, retention times, retention indices, structured chromatograms and standards. Subsequently, the aroma qualities of Xihu Longjing tea samples were discriminated by sensory evaluation combined with multivariate analysis. The study results indicated that 37 compounds were positively correlated with aroma quality, and 65 compounds were negatively correlated with aroma quality. The above compounds with various odor characteristics were considered as the key components to affect the aroma quality of Xihu Longjing tea.
✓ 已验证
产品关联
DOI
高影响因子
ANALYST
·
2016
·Vol. 141
·期 19
·5511-5519
·
IF 4.033
Miao Chen,Hua Yang,Liya Rong,Xiaoqing Chen
A novel facile method for on-site determination of sulphite in wine using a gas-diffusion microfluidic paper-based analytical device (μPAD) combined with surface-enhanced Raman spectroscopy (SERS) was explored. The inexpensive and disposable μPAD was realized by sandwiching the ZnO-paper disc and integrating gas-diffusion separation and gas preconcentration on a paper-based platform. Through extensive condition optimization, the SERS signal at a shift of 620 cm−1 and the concentration of SO2 showed good linearity in the range of 5–300 μg mL−1. The linear correlation coefficient was 0.995 and the detection limit for sulphite was found to be 2 μg mL−1. Ultimately, this proposed method was applied to the determination of sulphite in wine, which can be essentially paralleled with the official method. Endowed with portability, minimal reagent consumption, and operational simplicity, this developed device would find broad utilization for on-site monitoring of sulphite.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2017
·Vol. 146
·期 13
·
IF 2.965
Zhan Huaqi,Hu Yongjun,Wang Pengchao,Chen Jiaxin
Tetrahydropyran-2-methanol (THPM) is a typical alcohol containing a six-member cyclic ether, which can be considered as the model molecule of cyclic sugar. Herein, vacuum ultraviolet (VUV) photodissociation spectroscopy is employed to study fragmentation pathways and infrared (IR) plus VUV photoionization spectroscopy to investigate the structures of neutral THPM and its clusters with the size up to the trimer. Qualitative structural assignments are confirmed for the neutral species and ions based on MP2/aug-cc-pVTZ and ωB97X-D/cc-pVTZ calculations. The fragment cations at m/z = 84, 85, and 98 arise by the losing of CH 2 OH, CH 3 OH, and H 2 O from the monomer, respectively, as a result of C–C bond and C–O bond dissociation under the VUV (118 nm) radiation. It is found that the loss of CH 3 OH and H 2 O involves hydrogen transfer from the CH 2 group to the dissociating CH 2 and OH groups. Comparing the observed and calculated spectra of the monomer THPM, it suggests that the conformer containing a chair tetrahydropyran ring and an intramolecular hydrogen bond would be dominantly survived in a supersonic beam. Moreover, the IR spectra of larger clusters n > 1 (n = 2, 3) show only the broad hydrogen bonded OH stretch mode, and thus these larger clusters would form a closed-cyclic structure, where all OH groups are participating in hydrogen bonding. Partially the CH stretch positions of THPM clusters do not change significantly with the increasing of cluster size, thus the CH and CH 2 groups are not involved in H-bonding interactions.
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2016
·Vol. 40
·期 2
·514-523
·
IF 2.741
Chaoyi Wang,Pan Zou,Ting Zhang,Haipu Li,Zhaoguang Yang
In this work, an in situ acylation combined with solid-phase microextraction coupled to gas chromatography and mass spectrometry method has been developed for simultaneously determining haloanisoles (2,4,6-trichloranisole, 2,4,6-tribromoanisole), and their direct precursors (2,4,6-trichlorophenol, 2,4,6-tribromophenol) and indirect precursors (2-chloropenol, 2,4-dichlorophenol, 2-bromophenol, 2,4-dibromophenol) in water. The key parameters for the solid-phase microextraction were determined by using Plackett–Burman screening and optimized by central composite optimization. Under optimal conditions, the eight compounds can be analyzed in a short time (33 min) with a strong linearity ranging from 2 to 200 ng/L (correlation coefficient greater than 0.996), showing good sensitivities with the limit of detection in a range of 0.23–0.91 ng/L and a limit of quantification of 0.77–3.03 ng/L, good repeatability (2.00–9.10%) and interday precision (1.67–11.3%). When environmental water samples were treated, the recoveries of target compounds were 75.5–127.3%, suggesting that the developed method could be applied in probing the origin of haloanisoles and monitoring halophenols and haloanisoles in natural waters at concentration levels of ng/L.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Xu Zhao,Fuxin Yang,Wentao Li,Houzhang Tan,Lijuan Gao,Yanhao Jiao
With the urbanization and population growth, the disposal of plastic waste has become a significant challenge, as the traditional methods often result in pollution and resource wastage. Pyrolysis technology offers a sustainable solution by converting the waste plastics into valuable gas or liquid fuels. The co-pyrolysis of plastics and biomass is an effective approach for synergistically managing these two types of solid waste. The polyethylene (PE) and salix psammophila (SP) was used to investigate the gas production characteristics and polycyclic aromatic hydrocarbons (PAHs) formation during the co-pyrolysis. Additionally, Cu/ZSM-5, Co/ZSM-5, and Ni/ZSM-5 catalysts were employed to investigate the effects of different metal-loaded catalysts on the co-pyrolysis process. The results indicate that, with the increase of the pyrolysis temperature, the yield of gas-phase products gradually increases, solid residue decreases, and liquid-phase products initially increase before declining, reaching their maximum at 500 °C. The synergistic effect promotes the formation of C 2 H m (C 2 H 2 , C 2 H 4 , C 2 H 6 ) and CH 4 , leading to the increase of the gas-phase product yields compared to the individual pyrolysis. The addition of catalysts further enhances the gas production: Cu/ZSM-5 boosts H 2 yield, Co/ZSM-5 shows selectivity for CH 4 and C 2 H m , and Ni/ZSM-5 exhibits better selectivity for CO and H 2 . Under the various pyrolysis conditions, aromatic compounds and aliphatic hydrocarbons consistently dominate the liquid-phase products. With the increase of the pyrolysis temperature, the proportion of aliphatic hydrocarbons decreases, while the proportion of aromatic compounds increases. The addition of catalysts reduces the proportions of both aliphatic and aromatic compounds. PAHs generation is temperature-dependent, significantly increasing at 700 °C. At the low pyrolysis temperatures, the co-pyrolysis reduces PAHs yield, but at high temperatures, PAHs formation increases. The addition of catalysts decreases PAHs yield and toxicity equivalency. Cu/ZSM-5 promotes the cracking of two-ring PAHs, reducing two-ring PAHs yield. Co and Ni catalysts enhance the selective aromatization of small hydrocarbon molecules, forming low-ring PAHs and limiting PAHs aggregation. Overall, Ni/ZSM-5 demonstrates the best performance in enhancing gas production and reducing PAHs emissions, followed by Co/ZSM-5 and Cu/ZSM-5.
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Denghui Huang,Xiaolan Fu,Kaixin Wang,Zicheng Zheng,Liyuan Zhang,Zhizhen Ye,Jie Jiang,Zhong-kang Han,Liping Zhu
Oxygen vacancies play a crucial role in charge transport and surface states in semiconductor metal oxides, significantly influencing various research fields, such as photocatalysis and gas sensor. Developing effective strategies to generate oxygen vacancies and thereby enhance device performance is highly desirable. In this study, we proposed a water-based one-step electrospinning method to introduce hydroxyl groups, leading to the synthesis of Pt-decorated WO3 nanofibers (Pt-WO3(H2O)) with increased oxygen vacancies. Density functional theory calculations revealed that the dissociation energy of W–OH is lower than that of the W–O bonds, promoting the formation of oxygen vacancies via W–OH bond cleavage. These vacancies reduced the adsorption energy of acetone on the WO3 surface, enhancing surface interactions. Consequently, the Pt-WO3(H2O) sensor exhibited an ultrahigh response of 82 to 1.8 ppm acetone at 300 °C, which was about 1 order of magnitude higher than the one fabricated by conventional electrospinning. These findings indicate that water-based electrospinning is an effective technique for generating oxygen vacancies in metal oxide nanofibers. Our high-performance acetone sensor, capable of detecting low concentrations, holds great potential for applications in noninvasive health screening.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Chemistry-X
·
2024
·
IF 6.5
Leng Han,Guijie Li,Xuting Wang,Bo Yu,Tenghui Zhang,Yujiao Cheng
Citrus black spot ( Phyllosticta citricarpa, CBS) is an important fungal disease that causes rind blemishes and affects quality of citrus fruits. The response of citrus to CBS in terms of volatiles was evaluated using molecular sensory science approaches. Fifty and twenty-one volatiles were identified in the orange juice and essential oil samples, respectively, via gas chromatography–mass spectrometry (GC–MS). The total volatile content in the samples increased after CBS infection, especially in the severe-infection group (SEG) juice and moderate-infection group (MOG) essential oil, which reached the highest levels. CBS enhanced floral, fruity, and off-flavor aromas and decreased the green aroma in citrus juice. Citrusy, floral, and green aromas increased in the CBS-infected essential oil. Six/five potential markers were screened in citrus juice/essential oil, respectively using the orthogonal partial least-square discriminant analysis (OPLS-DA) model. The changes in aroma profile and the difference in infection levels in citrus were attributed to these odorants.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Huiyan Zhang,Shanshan Shao,Mengmeng Luo,Rui Xiao
Catalyst deactivation is the main reason for low petrochemical yield in catalytic fast pyrolysis (CFP) of biomass. ZSM-5 catalysts modified by chemical liquid deposition (CLD) and acid dealumination (AD) were prepared to improve petrochemical yields for CFP of pinewood. The results showed that CLD by SiO 2 led to the coverage of strong acid sites, while AD favored the removal of superficial acid sites. CFP of pinewood showed that the relative area ratio of BTX was boosted by 37.2% and 30.4% over modified ZSM-5 catalysts by CLD and AD, respectively. The yield of indenes and naphthalenes which were important precursors of heavy coke decreased sharply. Considering environmental cost and catalytic performance, CLD seems to be a preferable modification method over ZSM-5 in the catalytic pyrolysis of biomass for petrochemicals.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Metabolites
·
2024
·Vol. 14
·期 4
·176
·
IF 3.4
Yuan Jing,Wei Chen,Xuebai Qiu,Shuyue Qin,Weichang Gao,Chaochan Li,Wenxuan Quan,Kai Cai
The quality of crops is closely associated with their geographical location and yield, which is reflected in the composition of their metabolites. Hence, we employed GC–MS pseudotargeted metabolomics to investigate the metabolic characteristics of high-, medium-, and low-yieldNicotiana tabacum(tobacco) leaves from the Bozhou (sweet honey flavour) and Shuicheng (light flavour) regions of Guizhou Province. A total of 124 metabolites were identified and classified into 22 chemical categories. Principal component analysis revealed that the geographical location exerted a greater influence on the metabolic profiling than the yield. Light-flavoured tobacco exhibited increased levels of sugar metabolism- and glycolysis-related intermediate products (trehalose, glucose-6-phosphate, and fructose-6-phosphate) and a few amino acids (proline and leucine), while sweet honey-flavoured tobacco exhibited increases in the tricarboxylic acid cycle (TCA cycle) and the phenylpropane metabolic pathway (p-hydroxybenzoic acid, caffeic acid, and maleic acid). Additionally, metabolite pathway enrichment analysis conducted at different yields and showed that both Shuicheng and Bozhou exhibited changes in six pathways and four of them were the same, mainly C/N metabolism. Metabolic pathway analysis revealed higher levels of intermediates related to glycolysis and sugar, amino acid, and alkaloid metabolism in the high-yield samples, while higher levels of phenylpropane in the low-yield samples. This study demonstrated that GC–MS pseudotargeted metabolomics-based metabolic profiling can be used to effectively discriminate tobacco leaves from different geographical locations and yields, thus facilitating a better understanding of the relationship between metabolites, yield, and geographical location. Consequently, metabolic profiles can serve as valuable indicators for characterizing tobacco yield and geographical location.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Leizhi Zheng,Xiemin Liu,Guoqiang Yang,Jia Liu,Bowen Jiang,Ying Liu,Xinyao Li,Xingbang Hu,Zhibing Zhang
The cycloaddition reaction of CO 2 in traditional reactors is relatively slow due to insufficient gas–liquid contact. In this work, the microdroplet reactor was set up to research the intensification effect of increasing the volumetric mass transfer coefficient on the reaction. The [C 1 C 2 Im][I]/PhOH (1-ethyl-3-methylimidazolium iodide/Phenol) with a molar ratio of 2:1 exhibited excellent catalytic activity at room temperature. Up to 85% conversion of the substrate could be achieved in the microdroplet intensification device. The intensification reaction model of the microdroplet was established, which explored the effect of the microdroplet size and gas–liquid mass transfer on the reaction. The increase of the volumetric mass transfer coefficient ( k La ) could improve the efficiency of the reaction at the gas–liquid interface of the microdroplet. The mathematical model of the microdroplet intensification reaction was established to clarify the intensification mechanism.
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xue-Chun Yang,Xuan Yao,Shaqi Fu,Yuyan Cao,Tingzhan Wang,Martin Köckerling,Lingli Cheng,Zheng Jiao,Jing-Tai Zhao
Ethylene glycol (EG) is a widely used material, but its vapor is harmful to human health already in low concentrations. Thus, highly sensitive EG gas sensors are urgently needed. Herein, a series samples of ZnO and carbon dots (CDs) were synthesized at different ratios through a simple mechanical grinding method. The senor made using ZnO/CDs2 exhibits an ultra-high response (Ra/Rg) to 100 ppm EG up to 2798, 1378 and 467, and extremely low detection limit as low as 21 ppb, 13 ppb and 2 ppb, under UV light, visible light, and infrared light, respectively, as well as excellent repeatability and long-term stability. Especially, under UV light irradiation, the response of ZnO/CDs2 to 100 ppm EG is 24 times that of pure ZnO (Ra/Rg = 114.7), and more than 71 times that of 9 other gases. The outstanding gas sensing performance of ZnO/CDs2 can be attributed to the excellent light response ability of CDs at first, which greatly enriches the electron concentration in ZnO/CDs under light irradiation. Furthermore, the photo-induced electron transfer (PET) property of CDs and the p-n heterojunction formed at the interface between ZnO and CDs play a key role in rapid electron transport and transfer, avoiding a large number of electron hole recombination.
✓ 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）