CHROMATOGRAPHIA
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2019
·Vol. 82
·期 10
·1523-1529
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IF 1.552
Zhang Wei,Fang Sheng,Liang Xianrui
A relatively new application of natural deep eutectic solvents (NADESs) as eco-friendly dilution mediums in static headspace gas chromatography (SHS-GC) was further studied. The partition coefficients of twelve organic solvents in NADESs were determined by SHS-GC. Eight NADESs were prepared with choline chloride and carboxylic acids, polyols and urea in different molar ratios. The twelve organic solvents included four haloalkanes, four aprotic solvents, two alcohols, and two alkanes. The partition coefficients ( K ) of each solvent in different NADESs were determined and discussed. The log K values of alkanes and aprotic solvents in NADESs were low, while the log K of haloalkanes and alcohols was high. That is, alkanes and aprotic solvents in NADESs had better headspace efficiency, indicating that the interaction between the solvents and the NADESs played an important role. The relationship between the log K and the properties of NADESs and organic solvents was further discussed. As an example, the method was applied to determine the residual solvents in paroxetine by SHS-GC with appropriate NADES. This study is beneficial for the selection of suitable NADESs as green mediums for the detection of residual solvents in pharmaceuticals.
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Yuhai Sun,Jingjing Li,Peirong Chen,Bangfen Wang,Junliang Wu,Mingli Fu,Limin Chen,Daiqi Ye
Palladium-loaded ZnO (Pd/ZnO) catalyst was synthesized by co-precipitation method and evaluated for plasma-catalytic reverse water-gas shift (RWGS) reaction. A CO 2 conversion of 32.5 % was achieved on “Pd/ZnO + Plasma”, and was around two times higher than that of “ZnO + Plasma” (17.3 %). Catalyst characterization by X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction and quasi in situ X-ray photoelectron spectroscopy revealed the possible formation of ZnO x @PdZn (ZnO x decorated PdZn alloy) at the interface of Pd active phase and ZnO support. The role of ZnO x @PdZn in plasma-catalytic CO 2 conversion was systematically investigated by plasma-excited CO 2 temperature-programmed desorption and in situ Fourier transform infrared spectroscopy. It was found that ZnO x @PdZn at Pd-ZnO interface improved significantly plasma-catalytic CO 2 conversion by promoting the production of bidentate carbonate and bidentate formate species. In situ Raman spectroscopy studies proved that the ZnO x @PdZn remained largely intact during the RWGS process. Our in situ spectroscopic findings thus unveil that the ZnO x @PdZn at Pd-ZnO interface favors the activation of CO 2 , and, consequently, leads to a higher plasma-catalytic performance for CO 2 conversion.
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高影响因子
JOURNAL OF FOOD SCIENCE
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2019
·Vol. 84
·期 9
·2402-2411
·
IF 2.081
Bi Chen,Xiaoming Wang
Diuron is a urea herbicide that is frequently detected in surface water, groundwater, and marine waters. However, there are few methods or guidelines reported on ensuring the quality of sugarcane and soil. In this study, a method was developed for detecting diuron to ensure the quality and safety of food and sugar. Mass spectrometry was used to identify 3,4-dichloroaniline as a marker for the thermal decomposition of diuron, and thus, as a representative component for quantitative diuron analysis. This approach can be used to rapidly detect trace amounts of diuron. In addition, ultrasound-assisted extraction (UAE) and carbon nanotube column purification were used in conjunction with gas chromatography–electron capture detection to detect diuron. The method was then evaluated for its accuracy, detection limit, and viability. The effects of extraction solvent, ultrasound time, and ultrasound power on the extraction efficiency of the analyte from sugarcane and soil were also investigated. The efficiency and optimum conditions of UAE were examined through single-factor experiments and Box–Behnken design (BBD). The optimal extraction conditions were identified as follows: acetonitrile as the extraction solvent, extraction temperature of 27 °C, extraction time of 3.4 min, and ultrasound power of 70 W. Under these conditions, high linearity was achieved for diuron concentrations of 0.01 to 5.0 mg/L, and the purification correlation coefficient was consistently greater than 0.998. Hence, gas chromatography, combined with UAE and BBD, offers superior efficiency extraction, which is sufficiently accurate and precise for pesticide residue analysis. Practical Application We developed an accurate and cost-effective method for detecting diuron (a commonly used herbicide) in soil and sugar samples. We performed experiments to determine the optimum detection conditions for our method. This method can be used for online monitoring of sugar manufacturing processes to ensure food safety and quality.
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PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 43
·期 5
·2220-2230
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IF 3.201
Yan Gong,Xiaofeng Wu,Jiayuan Chen,Wenhui Li,Ning Han,Donghai Zhang,Yunfa Chen
Core–shell metal@ZnO nanoparticles including Au@ZnO, Pd@ZnO and Pt@ZnO were synthesized and utilized for sensing low-concentration benzene. Various techniques were used to characterize the compositional properties of the typical core@shell structure and analyze the relation between the sensing properties and the metal–ZnO hetero-interfaces. When applied as gas-sensing materials, all three core–shell metal@ZnO nanoparticles showed better sensing performance than pure ZnO nanoparticles towards low concentration benzene. In particular, the gas-sensing response of the Pt@ZnO core–shell nanoparticles was 7 times higher than that of pure ZnO towards 0.1 ppm benzene and 63 times higher towards 5 ppm benzene, which was more sensitive than most gas-sensing materials in previous literature. Furthermore, the Pt@ZnO core–shell nanoparticles presented an ultra-low detection limit of no less than 10 ppb, which was lower than those of most gas-sensing materials in previous literature. Besides, the Pt@ZnO core–shell nanoparticles showed high selectivity and long-term response stability with a response value of 2.7 ± 1.6% towards 1 ppm benzene after operating for a month. The enhanced gas-sensing performances of the metal@ZnO core–shell nanoparticles are well correlated to the work function differences between the contacted metal and ZnO within the metal–ZnO hetero-interfaces, which produce high Schottky energy barriers and modulate the electron transfer.
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JOURNAL OF CHROMATOGRAPHY A
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2018
·
IF 3.716
Dandan Li,Man He,Beibei Chen,Bin Hu
In this work, magnetic nanoporous carbons (MNPCs) based on Zn/Co-MOFs was synthesized via a facial one-step carbonization method. The prepared MNPCs exhibited high specific surface areas, good chemical stability and high extraction efficiency for interest organophosphorus pesticides (OPPs). The good extraction performance of the MNPCs for interest OPPs can be primarily attributed to π-π interaction and hydrophobic interaction between MNPCs and OPPs. Based on it, MNPCs-based MSPE-GC-FPD method was established for the quantification of five OPPs in fruit samples. The main experimental conditions for MSPE of five target OPPs were investigated systematically and optimized, such as the desorption solvent and volume, extracted volume, ionic strength, extraction time and desorption time. Under the optimal conditions, the limits of detection (LODs, S/N = 3) were found to be in the range of 0.018 (ethion) -0.045 (malathion) μg/L. The linearity was 0.05-100 μg/L for phorate, diazinon, ethion and 0.1-100 μg/L for malathion, fenthion respectively. The reproducibility of the method was in the range of 3.5-9.7%. The recovery experiments were carried out by spiking target OPPs at three concentration levels to validate the accuracy of the proposed method, and the recoveries for target OPPs were 84-116%. The results show that the proposed method in this work can be successfully used to analyze OPPs residue in fruit sample.
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PubMed
高影响因子
Food Analytical Methods
·
2015
·Vol. 9
·期 1
·16-22
·
IF 1.956
Fan Yingming,Ma Xiaoguo,Li Zhongyang,Chen Meiqin
A sensitive and reliable method was proposed for the simultaneous detection of melamine, ammeline, ammelide, and cyanuric acid in fish and shrimp by gas chromatography–mass spectrometry after fast derivatization. The analytes were derivatized using a 99:1 mixture of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and trimethylchlorosilane (TMCS) under microwave irradiation for 2 min with a power of 700 W, followed by determination with gas chromatography–mass spectrometry in selected ion monitoring mode. Conditions for extraction and derivatization of melamine and related compounds were investigated and optimized. Under the optimal experimental conditions, the limits of detection (LODs, S/N = 3) for melamine, ammeline, ammelide, and cyanuric acid were 0.006, 0.012, 0.013, and 0.010 mg kg −1 , respectively. The developed method was successfully applied to determine melamine and related compounds in fish and shrimp samples, and the spike recoveries were 82.5–103.1 % with relative standard deviations (RSDs) ( n = 3) of 0.6–4.1 %.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2015
·
IF 3.564
Zhongping Huang,Peipei Zhang,Yang Sun,Yilei Huang,Zaifa Pan,Lili Wang
A novel method on basis of thin layer chromatography (TLC) combined with on-line pyrolytic methylation gas chromatography (OPM–GC) in the presence of trimethylsulfonium hydroxide (TMSH) was developed and applied to the determination of glyceride and free fatty acid residuals in biodiesel. Both glycerides and free fatty acids in biodiesel were separated by TLC alumina sheets, and then the cut spots were analyzed directly by pyrolytic methylation gas chromatography method in a pyrolyzer at 350 °C without complex pretreatment. In this process, glycerides and free fatty acids were converted into their corresponding fatty acid methyl esters, and quantified well by the total peak areas of formed esters. Thus obtained calibration curves of monostearin, distearin, tristearin and oleic acid exhibited good linearity with the regression coefficients from 0.9766 to 0.9950 at the concentrations ranged from 300 to 5000 mg L −1 . The limits of detection were in the range of 100–200 mg L −1 , and the RSDs ( n = 3) ranged from 3.7% to 12.5%, calculated for monostearin, distearin, tristearin and oleic acid at the concentration level of 2000 mg L −1 . The potential of the proposed method was assessed by the determination of glycerides and free fatty acids in real biodiesel samples. The results prove that this TLC–OPM–GC technique is a simple, accurate and low solvent consuming method for the simultaneous determination of glyceride and free fatty acid residuals in biodiesel.
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CHINESE JOURNAL OF CHEMISTRY
·
2013
·Vol. 31
·期 10
·1329-1335
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IF 0.917
Saisai Hong,Wenyu Kang,Yue Su,Yinlong Guo
In the traditional research of volatile compounds, some trace-level compounds could not be identified by gas chromatography-mass spectrometry. Target and post-targeted methods were applied in the investigation of trace-level volatile compounds in fresh turf crop ( Lolium perenne L.) based on gas chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry. According to literatures published, a target analysis was performed by using retention index, accurate masses of characteristic ions and second-stage mass spectra (MS 2 spectra). And a series of experiments showed that low electron impact energy was beneficial to the improvement of the abundances of low abundance molecular ion peak. Enhancing the abundances of low abundance molecular ion peak was beneficial to qualitative analysis. Totally, 60 volatile compounds were identified, the great majority compounds of which were benzeneacetaldehyde (14.8%), 2,5-dimethyl-pyrazine (9.6%), and hexanal (9.3%). Identification was complied by mass spectral search, retention index and accurate masses of characteristic ions.
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高影响因子
MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 3
·1187-1194
·
IF 4.831
Yang Genggeng,He Zeying,Liu Xueke,Liu Chang,Zhan Jing,Liu Donghui,Wang Peng,Zhou Zhiqiang
Magnetic polymer nanospheres were prepared and used as adsorbents for the extraction of organochlorine and pyrethroid pesticides from water samples. The adsorbents were synthesized by miniemulsion polymerization of N-vinylimidazole and divinylbenzene and simultaneous encapsulation of oleic acid-coated Fe 3 O 4 nanoparticles. Following desorption with ethyl acetate, the target analytes β-hexachlorocyclohexane, δ-hexachlorocyclohexane, p,p’-DDE, heptachlor, trans-chlordan, cis-chlordan, bifenthrin, β-cypermethrin, δ-methrin, λ-cyhalothrin and esfenvalerate were determined by gas chromatography with electron capture detection. Desorption conditions, extraction times and sample volume were screened by Plackett-Burman design and optimized by Box-Behnken design. Under the optimum conditions, the organochlorines can be quantified in the 20 to 400 ng L −1 concentration range, and the pyrethroids in the 400 to 4000 ng L −1 concentration range. The recoveries of organochlorines and pyrethroids from spiked real water samples are between 77.6 and 97.3 %, with relative standard deviations between 0.9 and 10.0 %. The method for magnetic solid phase extraction described here is fast, simple and friendly to the environment.
Fe 3 O 4 nanoparticles coated with oleic acid (OA) were covered with a copolymer prepared from N-vinylimidazole (VI) and divinylbenzene (DB), and then used for magnetic solid phase extraction of organochlorine and pyrethroid pesticides. Recoveries from spiked water samples range from 77.6 to 97.3 %.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Qianrou Zhang,Guangzhou Qu,Tiecheng Wang,Chungang Li,Hong Qiang,Qiuhong Sun,Dongli Liang,Shibin Hu
Humic acid (HA), a predominant type of natural organic matter in surface water, had several potential environmental and health risks. A gas phase surface discharge plasma system was employed to eliminate HA from micro-polluted surface water, and the effects of some concomitant inorganic ions on HA removal were evaluated. The experimental results showed that approximately 89.4% of HA could be smoothly eliminated after 40 min of the discharge plasma treatment, and the HA removal process could be fitted well by the first-order kinetic model. The presence of anions such as CO 3 2− and Cl − in the natural water were adverse for the HA removal due to their competition for the active species, whereas the effects of NO 3 − and SO 4 2− on the HA removal could be neglected; this deduction was also confirmed via the evolution of fluorescence spectra intensity of OH radicals. Although Cu 2+ could react with H 2 O 2 via Fenton-like reaction, its presence was still adverse for the HA removal due to the complexing effect of Cu 2+ with HA molecules. In addition, the HA removal processes were characterized by UV–Vis spectrum, DOC removal, specific absorbance parameters, and three-dimensional fluorescence spectrum analysis.
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高影响因子
ANALYTICAL LETTERS
·
2024
·
IF 1.6
Tongtong Liu,Weina Han,Lulu Wang,Xiaoyu Hou,Jin Cao
The aim of this study was to optimize the extraction conditions of 15 preservative allergens from skincare products using response surface methodology (RSM) and determination by gas chromatography – tandem mass spectrometry (GC-MS/MS). The optimal parameters were: 50% acetonitrile (ACN) (% v/v), a solvent/sample ratio of 80, and an extraction time of 10 min. The method provided good linearity (R2 ≥ 0.990) from 0.01 to 2 µg/mL with low limits of detection (0.02–0.2 mg/kg) and quantification (0.04–1 mg/kg). Recoveries ranged from 70.1 to 125.6% and the relative standard deviations (RSDs) varied from 2.0 to 14.9%. The method was successfully applied to eighty skincare products to accurately quantify these preservatives allergens.
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高影响因子
Gas Science and Engineering
·
2024
·
IF 0
Fang Wang,Wenjing Lin,Jinchi Mu,Xiaosheng An,Ruiyang Zhang,Lihong Guo,Ying Zhou
Capturing CO 2 emitted from industrial power plants is the most efficient method for reducing global carbon emissions at present. In this work, the enhanced dynamic mechanism of CO 2 capture from flue gas has been investigated through IB group transition metal functionalized carbon nanotubes (CNTs) as kinetic accelerators via the hydrate-based approach in combination with theoretical calculations and experiments. The computational results revealed that the both the hydrophilic oxygen-containing group and Cu modified CNTs not only enhanced the CO 2 adsorption ability but also exhibited high selectivity towards CO 2 . Importantly, experiments demonstrated that the multi-walled carbon nanotubes (MWCNTs) based accelerators significantly enhanced the dynamic performance of the hydrate formation , substantially increasing gas consumption and CO 2 separation efficiency. Particularly, the theoretical selected Cu@FMWCNTs mixed with THF accelerators exhibited superior kinetic indexes during the hydrate formation even under relative low pressure at 1.5 MPa with the largest CO 2 separation efficiency of 76.49%, which showed Cu@FMWCNTs to be a potential kinetic accelerator for CO 2 capture. This study could provide valuable findings for nanomaterial design of novel hydrate accelerators and facilitate the development of the hydrate-based technology for CO 2 capture from the economic perspective of low energy consumption.
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