JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2019
·
IF 2.813
Yanwei Fu,Xiaowen Dou,Lei Zhang,Jiaan Qin,Meihua Yang,Jiaoyang Luo
Developing an analysis of multi-pesticide residues for different herbal species-ready applications is a challenge. In the present work, a comprehensive analysis was proposed for rapid detection of 201 pesticides in various medicinal herbs. Samples were extracted and cleaned up with a high throughput pretreatment approach (modified QuEChERS), and then detected by gas chromatograph coupled to an electron impact ionization triple quadrupole mass spectrometer (GC-EI-MS/MS). The clean-up procedure has been optimized using four types of representative medicinal herbs with different primary or secondary metabolites . Moreover, a mixture of analyte protectants (APs) was to improve the peak shape and intensity of some compounds. The performance of the method was validated according to the European Union SANTE/11813/2017 regulatory guidelines. The limit of quantification (LOQ) was determined to be ≤10 ng mL − 1 , and the recovery was between 70.0%–120.0%, with ≤20% RSD for the majority of pesticides. Sixty samples belonging to different species of medicinal herbs (such radix, flos, cortex, fructus, and seeds) were analyzed to evaluate the applicability of the optimized method. High frequency of chlorpyrifos was found in Citri reticulatae pericarpium, Crataegi fructus and Cuscutae semen samples.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
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IF 7.7
Jinju Ma,Yupeng Liu,Juan Xu,Youqing Chen,Lanxiang Liu,Hong Zhang
Fresh-cut products are extremely perishable due to the processing operations, and the atmosphere environment, especially CO 2 , O 2 and H 2 O, could profoundly affect their shelf life. Herein, an insect “lac blanket”-mimetic and facile strategy was proposed for fresh-cut vegetables preservation, employing porous shellac hydrogel microparticles as gas “switches” in chitosan film to regulate CO 2 , O 2 and H 2 O vapor permeability. Thus, the shellac hydrogel/chitosan hybrid film presented the controllable and wide range of gas permeability, compared with the chitosan film. The shellac-COOH nanoscale vesicles aggregated to form shellac hydrogel network via hydrophobic binding. The shellac hydrogel microparticles played a certain lubricating effect on the hybrid film casting solution. The hydrogen bond network between shellac hydrogel and chitosan contributed to the excellent mechanical properties of the hybrid film. The hybrid film also exhibited remarkable water-resistant, antifogging properties, optical transparency and degradability. The hybrid packaging films prepared through this strategy could adjust the internal gas (CO 2 , O 2 , H 2 O and ethylene) contents within the packages, and further exhibited admirable preservation performance on three fresh-cut vegetables with different respiratory metabolisms. This gas permeation-controlled strategy has great potential in fresh food preservation and various other applications that need a modified atmosphere.
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FOOD RESEARCH INTERNATIONAL
·
2024
·
IF 7
Shiya Gan,Yingqi Chen,Lei Zhao,Xiaoyi Zhao,Tong Qiu,Xiaoting Zhai,Qianying Dai
Chinese Xiaokeng green tea (XKGT) possesses elegant and fascinating aroma characteristics, but its key odorants are still unknown. In this study, 124 volatile compounds in the XKGT infusion were identified by headspace-solid phase microextraction (HS-SPME), stir bar sorptive extraction (SBSE), and solvent extraction-solid phase extraction (SE-SPE) combined with gas chromatography-mass spectrometry (GC–MS). Comparing these three pretreatments, we found HS-SPME was more efficient for headspace compounds while SE-SPE was more efficient for volatiles with higher boiling points. Furthermore, SBSE showed more sensitive to capture ketones then was effective to the application of pretreatment of aroma analysis in green tea. The aroma intensities (AIs) were further identified by gas chromatography–olfactometry (GC-O). According to the AI and relative odor activity value (rOAV), 27 compounds were identified as aroma-active compounds. Quantitative descriptive analysis (QDA) showed that the characteristic aroma attributes of XKGT were chestnut-like, corn-like, fresh, and so on. The results of network analysis showed that ( E , Z )-2,6-nonadienal, nonanal, octanal and nerolidol were responsible for the fresh aroma. Similarly, dimethyl sulfide, ( E , E )-2,4-heptadienal, ( E )-2-octenal and β -cyclocitral contributed to the corn-like aroma. Furthermore, indole was responsible for the chestnut-like and soybean-like aroma. This study contributes to a better understanding of the molecular mechanism of the aroma characteristics of XKGT.
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JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 9
·1570-1576
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IF 2.737
Yuanyuan Feng,Faqiong Zhao,Baizhao Zeng
A polycarbazole film was electrodeposited on a stainless-steel wire from a solution of N , N -dimethylformamide/propylene carbonate (1:9 v/v) containing 0.10 M carbazole and 0.10 M tetrabutylammonium perchlorate. The obtained polycarbazole fiber was immersed into an ionic liquid (1-hydroxyethyl-3-methyl imidazolium bis[(trifluoromethyl)sulfonyl]imide) solution (in dimethylsulfoxide) for 30 min, followed by drying under an infrared lamp. The resulting polycarbazole/ionic liquid fiber was applied to the headspace solid-phase microextraction and determination of aromatic esters by coupling with gas chromatography and flame ionization detection. Under the optimized conditions, the limits of detection were below 61 ng/L (S/N = 3) and the linear ranges were 0.061−500 μg/L with correlation coefficients above 0.9876. The relative standard deviations were below 4.8% ( n = 5) for a single fiber, and below 9.9% for multi-fiber ( n = 4). This fiber also exhibited good stability. It could be used for more than 160 times of headspace solid-phase microextraction and could withstand a high temperature up to 350°C.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Kai Zhang,Shuhang Ren,Xin Yang,Yucui Hou,Weize Wu,Yuyun Bao
Four thermostable functional deep eutectic solvents (DESs) based on imidazole (Im), 2-methylimidazole, 2-ethylimidazole, and 2-propylimidazole as hydrogen bond acceptor (HBA) and glycerol (Gly) as hydrogen bond donor (HBD) were prepared. All prepared DESs can efficiently capture low-concentration SO 2 . The SO 2 solubility increased with decreasing temperature and increasing SO 2 concentration and the available absorption of 2000 ppm SO 2 in Im-Gly DES was high, up to 0.634 mol of SO 2 /mol of Im (0.161 g of SO 2 /g of DES) with n Im : n Gly = 1:2 at 40 °C. The regeneration experiments showed that the SO 2 absorption capacities in Im-Gly DES did not change after 5 absorption/desorption cycles. Furthermore, the absorption mechanism based on 1 H NMR and FTIR analyses indicated that there was an acid–base interaction between SO 2 and Im.
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Journal of Central South University
·
2016
·Vol. 23
·期 1
·59-67
·
IF 0.562
Zou Pan,Wang Lin,Yang Zhao-guang,Lee Hsiaowan,Li Hai-pu
A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction (HSSPME) coupled with gas chromatography-maßs spectrometry (GC-MS). Ten off-flavor compounds, including geosmin (GSM), 2-methylisoborneol (2-MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), β -ionone, trans-2,cis-6-nonadienal (NDE), 2,3,4-trichloroanisole (2,3,4-TCA), 2,3,6-trichroloanisole (2,3,6-TCA), 2,4,6-trichloroanisole (2,4,6-TCA), and 2,4,6-tribromoanisole (2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity (r 2 =0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.
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JOURNAL OF HAZARDOUS MATERIALS
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2017
·
IF 6.065
Songjian Zhao,Jian Mei,Haomiao Xu,Wei Liu,Zan Qu,Yong Cui,Naiqiang Yan
Metal-organic frameworks (MOFs) adsorbent Mil-101(Cr) was introduced for the removal of elemental mercury from sintering flue gas. Physical and chemical characterization of the adsorbents showed that MIL-101(Cr) had the largest BET surface area, high thermal stability and oxidation capacity. Hg 0 removal performance analysis indicated that the Hg 0 removal efficiency of MIL-101(Cr) increased with the increasing temperature and oxygen content. Besides, MIL-101(Cr) had the highest Hg 0 removal performance compared with Cu-BTC, UiO-66 and activated carbon, which can reach about 88% at 250 °C. The XPS and Hg-TPD methods were used to analyze the Hg 0 removal mechanism; the results show that Hg 0 was first adsorbed on the surface of Mil-101(Cr), and then oxidized by the open metal site Cr 3+ . The generated Hg 2+ was then combined surface adsorbed oxygen of adsorbent to form HgO, and the open metal site Cr 2+ was oxidized to Cr 3+ by surface active oxygen again. Furthermore, MIL-101(Cr) had good chemical and thermal stability.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2017
·
IF 2.603
Zigang Tang,Lanling Chu,Yu Wang,Yuan Song,Ping Liu,Jinhui Fan,Jinjin Huang,Xiongwei Liu,Lanlan Wei,Chen Li,Renshan Zhao,Xuejun Kang
In this paper, we developed a rapid and safe method based on packed-fiber solid-phase extraction (PFSPE) system coupled with gas chromatography-mass spectrometry for the determination of four phthalate esters (PAEs), diethyl-o-phthalate (DEP), dibutyl-o-phthalate (DBP), di (2-ethylhexyl) phathalate (DEHP), di- n -octyl phthalate (DNOP), in urine samples. The PAEs in urine samples (500 μL) were rapidly cleaned up from urines using polystyrene (PS) nanofibers packed micro-columns fitted on a PFSPE pretreatment device, which can process up to 12 samples simultaneously in 5 min. Under optimum conditions, satisfied recovery and relative standard deviation values (RSDs) were in the range of 80.4–111.7% and 1.5–10.9%, respectively. The limits of detection (LOD) and the limits of quantification (LOQ) were ranged from 0.1 to 0.5 ng mL −1 and 0.5–2 ng mL −1 , respectively. The well controlled matrix effect was also evaluated by comparing the signal response of the pure PAEs standards dissolved in methanol with the signal response of PAEs in the urine matrix. This new method was successfully applied to determine four PAEs in urine samples of overweight and normal-weight children, and an association between phthalates in urines and obesity was observed. Thus, the method seems to be a useful tool for monitoring of the level of urinary phthalate esters and also to support an evidence for further reasearch of obesity.
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Science China-Chemistry
·
2026
·
IF 9.8
Zhong Fengyi,Sheng Jianping,He Ye,Du Chenyu,Ma Xiaodan,Moghadam Majid,Sun Yanjuan,Dong Fan
Under mild continuous-flow gas-solid conditions, the direct conversion of gaseous nitric oxide (NO) in flue gas to pure ammonia (NH 3 ) is hindered by the challenges of sustaining continuous proton-electron coupling and transfer. Here, we develop a PtO x -TiO 2 photocatalyst featuring ultrafine PtO x clusters that sustain continuous electron transfer via dynamic PtO x /PtO ( x−δ ) redox cycling. Upon illumination, PtO x continuously captures photogenerated electrons to form PtO ( x−δ ) and injects them into NO antibonding orbitals, while the PtO x -TiO 2 interface simultaneously drives H 2 O dissociation to provide a steady proton flux. This persistent electron-proton coupling orchestrated by PtO x /PtO ( x−δ ) cluster interface promotes exciton dissociation, interfacial charge separation, and stepwise hydrogenation of NO to NH 3 . Under continuous-flow conditions with 200 ppm NO, PtO x -TiO 2 achieves 76.0% NO conversion, 808.25 mmol m −2 h −1 NH 3 yield, and 98.1% selectivity, representing a 9.1-fold enhancement over pristine TiO 2 and representing the current best performance in the gas-solid phase NO reduction for NH 3 synthesis. In situ spectroscopy and density functional theory (DFT) calculations reveal that the exceptional activity mainly stems from the facilitated electron-proton coupled transfer via the unique role of PtO x /PtO ( x−δ ) cluster. This work establishes a practical strategy for sustainable NO abatement with green NH 3 production without separation in gas-solid systems.
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ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Changjiang Liu,Hu Zang,Xin Liu,Haiyan Lu,Nan Yu,Baoyou Geng
Copper-based catalysts demonstrate distinctive multicarbon product activity in the CO2 electroreduction reaction (CO2RR); however, their low selectivity presents significant challenges for practical applications. Herein, we have developed a multilevel porous spherical Cu2O structure, wherein the mesopores are enriched with catalytic active sites and effectively stabilize Cu+, while the macropores facilitate the formation of a “gas–liquid–solid” three-phase interface, thereby creating a microenvironment with an increasing water concentration gradient from the interior to the exterior. Potential-driven phase engineering and protonation synergistically optimize the reaction pathway, facilitating a switch between CO and C2H4. At a low current density of 100 mA cm–2, the faradaic efficiency (FE) for CO reaches an impressive 96.97%. When the current density increases to 1000 mA cm–2, FEC2H4 attains 53.05%. Experiments and theoretical calculations indicate that at lower potentials, the pure Cu2O phase diminishes the adsorption of *CO intermediates, while weak protonation inhibits hydrogen evolution reactions, thereby promoting CO production. Conversely, at more negative potentials, the Cu0/Cu+ interface and strong protonation generate locally elevated concentrations of *CO and *COOH intermediates, which enhance C–C coupling and deep hydrogenation, ultimately improving selectivity toward C2+ products. This study provides novel insights into the rational design of copper-based catalysts for customizable CO2 electroreduction products.
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Catalysis Science & Technology
·
2025
·
IF 4.2
Dajian Li,Alfin Kurniawan,Tania Roy,Jin Wang,Cheng lan Liu,Ze Zhen Wang,Rong Zhen Mu,Chun Hui Zhou
The efficient production of allyl alcohol from glycerol is of great importance due to its significance as a valuable intermediate in chemical industries. While catalytic conversion of glycerol to allyl alcohol by solid acid catalysts, carbon deposition (coking) is prone to occur on the catalyst surface, leading to slow down the conversion process and fast deactivation of the catalyst. In this study, we obtained an efficient catalyst for the preparation of allyl alcohol from gas-phase glycerol by controlling the pore structure and surface acidity of the catalyst. The characterization results showed that hydrochloric acid and citric acid removed the silicon and aluminium elements from montmorillonite, and the acidity, pore volume, and surface area ratio of Na-MMT (SBET=34.5 m2 g-1, VT=0.19 cm3 g-1) of the porous montmorillonite(HA1MMT) catalyst were all improved (SBET=97.9 m2 g-1, VT=0.28 cm3 g-1); After adding MoOx and VOx, the selectivity of Mo/V-HA1MMT catalyst for allyl alcohol was improved. The XPS characterization results indicate that the synergistic effect of Mo and V can promote the transfer of electrons during the reaction process of glycerol conversion. Within 480 minutes of catalyzing glycerol dehydration reaction, Mo0.6V0.4(5)-HA1MMT was almost deactivated (Conv.= 19.5%, Sel.allyl alcohol=31.2%) due to carbon deposition. When the catalyst was doped with calcium and magnesium components, a new active phase CaMo4 was discovered on the catalyst, and the acidity of Ca0.5Mg0.5-Cat. (Cat. is Mo0.6V0.4(5)-HA1MMT) decreased to 214.0 μmol g-1. The coking resistance performance of Ca0.5Mg0.5-Cat. was improved, and after 660 minutes of reaction, the catalyst was deactivated (Conv.= 32.1%, Sel.allyl alcohol=30.1%) due to carbon deposition. During the 3rd catalyst regeneration test, Ca0.5Mg0.5-Cat. still maintained high activity (Conv.= 63.3%, Sel.allyl alcohol=35.2%, Sel.acrolein=31.2%). The results of this study indicate that suitable pore structure and acidity are crucial for designing a catalyst with coking resistance properties.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Meng Zhang,Xintong Lv,Tianqi Wang,Wenyuan Pei,Ying Yang,Feng Li,Duanduan Yin,Hui Yu,Xiangting Dong
In this paper, polyoxometalates (POMs) electron acceptors were introduced into a classical p-type gas sensitive ceramic-copper oxide (CuO). Then, we investigated the effect of phosphomolybdic acid (PMA) on the sensing performance of CuO gas sensors. The results show that by introducing PMA, the response of CuO gas sensor to 100 ppm ethanol gas can be effectively improved to 2.78. This promotion may be due to the electron trapping effect of PMA, which promotes the carrier migration and inhibits its recombination. Simultaneously, the response and recovery time of the sensor is only 5 s and 4 s. Other gas sensing parameters of the sensors were also comprehensively investigated. The mechanism analysis shows that PMA, as an electron-transport mediator, can trap electrons in the conduction band of CuO, generate shallow electron traps, and effectively inhibit the recombination of electrons and holes in CuO, thereby enhancing gas sensing performance. This work provides a new idea for the advance of CuO-based gas sensors with enhanced sensing sensitivity using polyoxometalates as electron acceptors .
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