JOURNAL OF SEPARATION SCIENCE
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2016
·Vol. 39
·期 11
·2146-2155
·
IF 2.741
Xiuzhi Bai,Ting Zhang,Haipu Li,Zhaoguang Yang
Chloroanisoles, particularly 2,4,6-trichloroanisole, are commonly identified as major taste and odor compounds in water. In the present study, a simple and efficient method was established for the simultaneous determination of chloroanisoles and the precursor 2,4,6-trichlorophenol in water by using low-density-solvent-based simultaneous dispersive liquid–liquid microextraction and derivatization followed by gas chromatography with electron capture detection. 2,4-Dichloroanisole, 2,6-dichloroanisole, 2,4,6-trichloroanisole, 2,3,4-trichloroanisole, and 2,3,6-trichloroanisole were the chloroanisoles evaluated. Several important parameters of the extraction-derivatization procedures, including the types and volumes of extraction solvent and disperser solvent, concentrations of derivatization agent and base, salt addition, extraction-derivatization time, and temperature were optimized. Under the optimized conditions (80 μL of isooctane as extraction solvent, 500 μL of methanol as disperser solvent, 60 μL of acetic anhydride as derivatization agent, 0.75% of Na 2 CO 3 addition w/v, extraction-derivatization temperature of 25°C, without salt addition), a good linearity of the calibration curve was observed by the square of correlation coefficients ( R 2 ) ranging from 0.9936 to 0.9992. Repeatability and reproducibility of the method were < 4.5% and <7.3%, respectively. Recovery rates ranged from 85.2 to 101.4%, and limits of detection ranged from 3.0 to 8.7 ng/L. The proposed method was applied successfully for the determination of chloroanisoles and 2,4,6-trichlorophenol in water samples.
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International Journal of Greenhouse Gas Control
·
2024
·
IF 4.6
Kang Shunji,Shen Zhi,Liu Baiqiang,Yi Qun,Ma Jun,Song Hao,Shen Xizhou
The petrochemical industry has a significant demand for high-purity hydrogen. It primarily obtained from the H 2 purification unit by using pressure swing adsorption (PSA) technology to recover H 2 from medium-temperature shifting gas (MTSG). The the coupled wet CO 2 separation-PSA process was introduced in this work, aiming to capture CO 2 from MTSG while simultaneously increasing the H 2 recovery rate. To enhance the desorption pressure of CO 2 separation unit in the coupled process to facilitate the storage or utilization of the captured CO 2 , firstly, a rigorous thermodynamic study was carried out to provide a theoretical basis for the development of an improved CO 2 solvent. Subsequently, a pilot-scale test was executed to validate the theoretical findings. Finally, the patented coupled process was implemented at an industrial scale for the first time. The results showed that the capacity of PSA unit for H 2 purification increased from 6800 to 12,000 tons per year and the H 2 recovery rate increased from 84.6 % to 93.6 %; the CO 2 desorption pressure increased from about 0.03 MPa (traditional Benfield process) to 0.15 MPa, which reduced the energy consumption of CO 2 compression, and the total average annual economic benefits increased by US $ 15.55 million.
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ACS Omega
·
2021
·
IF 3.512
Kai Zhang,Hui Yan,Ruina Liu,Ping Xiang,Ji Zhang,Kaifei Deng,Ping Huang,Zhenyuan Wang
The determination of cause of death (COD) is one of the most important tasks in forensic practice and is mainly based on macroscopical and microscopical morphological signatures. However, some CODs are hard to determine because the significant morphological signatures can be nonspecific, variable, subjective, or even absent in the real world. In this study, gas chromatography coupled with high-resolution mass spectrometry (GC–HRMS)-based untargeted metabolomics was employed to obtain plasma metabolic profiles of rats that died from anaphylactic shock (AS), mechanical asphyxia (MA), or sudden cardiac death (SCD). The metabolic alterations of each COD group compared to the control group were investigated using a principal component analysis, partial least-squares discriminant analysis, the Wilcoxon test, and fold change analysis. A range of differential features was screened, and 11, 8, and 7 differential metabolites were finally verified for the AS, MA, and SCD groups, respectively. We proposed some explanations that may account for these metabolic differences, including glucose metabolism, the tricarboxylic acid cycle, glycolysis, lipid metabolism, creatinine catabolism, and purine metabolism. Next, for each COD, we used its differential metabolites, which were obtained through comparisons of each COD group to the control group and represented the metabolic changes of the individual COD, to perform a receiver operating characteristic (ROC) analysis to preliminarily evaluate their ability to discriminate each COD group from the other COD groups. We found that creatinine in the AS group and malic acid and uric acid in the MA group might represent some specific metabolic changes for the relevant COD with high areas under the curve in the ROC curve analysis. Moreover, the combination panel for AS or MA also showed a good ability to discriminate it from the others. However, SCD had fewer metabolic signatures and was relatively harder to discriminate from the other CODs in our work. The preliminary study demonstrates the feasibility of GC–HRMS-based untargeted metabolomics as a promising tool to reveal metabolic changes in different death processes and to determine the complex CODs.
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Food Analytical Methods
·
2016
·Vol. 10
·期 3
·713-726
·
IF 2.167
Feng Yunzi,Su Guowan,Sun-Waterhouse Dongxiao,Cai Yu,Zhao Haifeng,Cui Chun,Zhao Mouming
The aim of this study was to develop an effective analytical procedure to analyse the aroma-active compounds of soy sauce using headspace solid-phase micro-extraction (HS-SPME) coupled to gas chromatography-mass spectrometry/olfactometry (GC-MS/O). Optimization of SPME focusing on type of fibre, exposure time, extraction temperature and ionic strength was supported by gas chromatography-mass spectrometry (GC-MS). The optimized HS-SPME conditions were as follows: carboxen/polydimethylsiloxane (CAR/PDMS) fibre, NaCl concentration of 270 g/L, extraction temperature of 45 °C and 30-min exposure time. Under these conditions, 25 aroma-active compounds were detected in soy sauce by HS-SPME-GC-O. 2-Methylbutanal (malty), 3-(methylthio)propanal (cooked potato-like), dimethyl trisufide (sulfury, cooked onion), 2-methoxyphenol (smoky) and 2-phenylethanol (flowery) were the most intense. The overall odour impression of the CAR/PDMS-fibre-derived SPME extract detected via human sniffing resembled that of original soy sauce. The intensity of aromas detected by D-GC-O correlated well with the total peak area of GC-MS analysis. Thus, SPME coupled with D-GC-O offers an automated facile method to allow in situ optimization of SPME performance and ultimately effective analysis of aromas.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2022
·
IF 5.895
Yaran Liu,Xu Qian,Jiangtao Xing,Na Li,Junlong Li,Qingyu Su,Yixin Chen,Bolin Zhang,Baoqing Zhu
This paper clarifies the contribution of lactones and volatile phenols to the aroma of nongrape wine. A target method for the simultaneous determination of these two kinds of volatiles in nongrape wines was developed using headspace-solid-phase microextraction (HS-SPME) combined with high-resolution gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap-MS). A high-resolution mass spectrometry database including 12 lactones and 11 volatile phenols was established for qualitative accuracy. Different matrix-matched calibration standards should be prepared for specific samples due to the matrix effects. The method was successfully validated and applied in three nongrape wines. Hawthorn wine contained more lactones (δ/γ-hexalactone, δ/γ-nonalactone, δ/γ-decalactone, γ-undecalactone, δ/γ-dodecalactone, C10 massoia lactone, and whiskey lactone), while blueberry wine contained more volatile phenols (especially 4-vinylguaiacol and 4-ethylguiaiacol). Goji berry wines contained certain concentrations of δ-nonalactone, γ-nonalactone, δ-hexalactone, and 3-ethyl phenol. This study demonstrated that HS-SPME-GC-Orbitrap-MS can be applied for the accurate quantification of trace aroma compounds such as lactones and volatile phenols in fruit wines.
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
·
2024
·
IF 5.6
Luheng Wang,Maoyuan Nan,Xisi Long
To realize the simultaneous measurement of gap and gas concentration between narrow curved surfaces, in this article, a flexible spiral sensing element based on $\alpha $ -Fe2O3-doped multiwalled carbon nanotubes (MWCNTs) (mass ratio is 100) coated with polytetrafluoroethylene (PTFE) is prepared by spraying and spin coating technology using polyimide (PI) film as the substrate. The spiral structure has eddy current effect under ac excitation, which is sensitive to the change in the gap between the sensing element and metal target. Meanwhile, the $\alpha $ -Fe2O3-doped MWCNTs can respond to gas. The experimental results indicate that the gas response values of impedance amplitude, impedance angle, and resistance are 0.509%, 0.216%, and 1.376% at ethanol vapor concentration of 5000 ppm when the curvature radius is 50 mm with a gap of 0.5 mm, respectively. The absolute/relative sensitivities of impedance amplitude and impedance angle to the gap are 175 $711.54~\pm ~1424.85~\Omega \cdot \text { mm}^{-1}$ /11.347% $\pm ~0.095{\%}\cdot \text { mm}^{-1}$ and $2.614^{\circ }~\pm ~0.015^{\circ }\cdot \text { mm}^{-1}$ /5.307% $\pm ~0.033{\%}\cdot \text { mm}^{-1}$ in the gap range of 0–0.5 mm, respectively. In addition, according to impedance complex plane diagram of the sensing element, a signal processing method based on R–X is proposed, and the ability of flexible spiral sensing element to simultaneously measure the gap and gas concentration between narrow curved surfaces is preliminarily verified.
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ANALYTICAL LETTERS
·
2020
·
IF 1.467
Rongcan Guo,Futian Yu,Chenghua Wang,Hongrui Jiang,Lian Yu,Mouming Zhao,Xiaoling Liu
Suansun is a sour Chinese traditional fermented bamboo shoot product popular in Central and South Asia due to its unique flavor. The volatile compounds and their odor-activities in suansun are unknowns, which hinders the control of the fermentation and causes variations in the flavor and other properties. In order to assess the odor characteristics of suansun and its unique volatile components, headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) and aroma extract dilution analysis (AEDA) coupled with gas chromatography-olfactometry (GC-O) were used in this study to analyze three types of suansun samples. The results showed that a total of 43 volatiles were identified and quantified. Sixteen compounds, including five alcohols, four aromatics, four aldehydes, two carboxylic acids, and one ester, had high odor activity values exceeding 1. Fifteen odorants, including four unknowns, were detected by AEDA; eight of these compounds, 1-octen-3-ol, geraniol, p-cresol, nonanal, decanal, (E)-2-nonenal, phenylethyl alcohol, and octanoic acid, had high flavor dilution factors exceeding 243. Triangle difference tests showed that a mixture of p-cresol and octanoic acid revealed a high similarity to one of the symbolic “fermentation” odors in commercial suansun. The composition of the unique odor of suansun is better understood, which provides a theoretical basis for solving the quality control problems existing in the production process and lays a foundation for the modern production of this important product.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Liushan Jiang,Jingwen Niu,Yue Zhang,Huanhuan Liu,Shiyu Huang,Shuai Yuan,Guangyu Dong,Lutong Bu,Denghao Song,Qingxiang Zhou
Phthalates (PAEs) are typical plasticizers, and widely used in various products. Because of their toxic effects such as carcinogenicity and endocrine disruption, they have become one of the most important public health hazards. It is vital to establish reliable methods for sensitively measuring PAEs at trace levels in the environment. In present study, a new magnetic metal organic framework functionalized MXene composite was designed (CoFe 2 O 4 @Ti 3 C 2 @MIL101(Cr)), in which NH 2 -MIL101(Cr) was successfully modified onto the surface of aldehyde-functionalized magnetic titanium carbide by Schiff base reaction. The prepared magnetic composite was used as the adsorbent for magnetic solid-phase extraction (MSPE) in combination with gas chromatography–triple quadrupole mass spectrometry (GC-MS/MS) for high-performance enrichment and sensitive measurement of seventeen PAEs. CoFe 2 O 4 @Ti 3 C 2 @MIL101(Cr) had favorable adsorption ability for PAEs, the adsorption of PAEs was multilayered and non-uniform, and followed the pseudo-second-order kinetic model and Redlich-Peterson isotherm model. Moreover, the results revealed that the lower temperature was more beneficial for the extraction of PAEs. The factors influencing the enrichment efficiencies of PAEs were investigated. Under the optimal experimental conditions, the constructed method exhibited prominent linearity over concentration range of 0.01–40 μg L −1 , and the limits of detection (LODs) were very low over range of 0.003–0.018 μg L −1 . The extraction efficiencies of seventeen PAEs were ranged from 44.2 % to 104 %. The established method was validated for determining PAEs in the different beverages, and DIBP (0.19 μg L −1 ) and DBP (0.44 μg L −1 ) were successfully detected in tea drinks, and the spiked recoveries of seventeen PAEs in real samples were in the range of 86.9 −100.2 %, with standard deviations less than 5.8 %. The enrichment factors were between 71 and 166. In short, the proposed method earned prominent sensitivity and high feasibility, and could be a credible, and valuable alternative for monitoring PAEs in the future.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Min Liu,Jing Jiang,Dalun Xu,Leiwen Xiang,Huawei Wu,Tao Jiang,Jinjie Zhang
The production and distribution of 2,5-dimethylpyrazine (2,5-DMP), a key volatile flavor compound, are associated with the frying of skipjack tuna steaks. In this study, an intestinal villus-like chip was fabricated to quantitatively detect 2,5-DMP in multiphase systems based on surface-enhanced Raman spectroscopy (SERS). The chip exhibited excellent SERS performance with an enhancement factor of 1.16 × 10 8 , excellent uniformity and reproducibility, and low detection limits of 6.49 pg/mL, 0.182, and 0.920 ng/mL for 2,5-DMP solid, liquid, and gas models, respectively. The results indicated the 2,5-DMP content with growth rates in the order of frying steam > frying steaks > frying oil, and the 2,5-DMP content in frying steam was linearly correlated (R 2 = 0.992) with the trend of the acid value and total polar compounds in frying oil. Therefore, this strategy for achieving the reliable detection of 2,5-DMP can assist in monitoring the frying process and food safety.
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MOLECULES
·
2024
·Vol. 29
·期 24
·5883
·
IF 4.2
Yiping Yan,Bowei Sun,Mengqi Wang,Yanli Wang,Yiming Yang,Baoxiang Zhang,Yining Sun,Pengqiang Yuan,Jinli Wen,Yanli He,Weiyu Cao,Wenpeng Lu,Peilei Xu
In order to characterize the volatile chemical components ofSchisandra chinensisprocessed by different Traditional Chinese Medicine Processing methods and establish fingerprint profiles, headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS) technology was employed to detect, identify, and analyzeSchisandra chinensisprocessed by five different methods. Fingerprint profiles of volatile chemical components ofSchisandra chinensisprocessed by different methods were established; a total of 85 different volatile organic compounds (VOCs) were detected in the experiment, including esters, alcohols, ketones, aldehydes, terpenes, olefinic compounds, nitrogen compounds, lactones, pyrazines, sulfur compounds, thiophenes, acid, and thiazoles. Principal component analysis (PCA), Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA), and Pearson correlation analysis methods were used to cluster and analyze the detected chemical substances and their contents. The analysis results showed significant differences in the volatile chemical components ofSchisandra chinensisprocessed by different methods; the Variable Importance in Projection (VIP) values of the OPLS-DA model and thePvalues obtained from one-way ANOVA were used to score and screen the detected volatile chemical substances, resulting in the identification of five significant chemical substances with the highestVIPvalues: Alpha-Farnesene, Methyl acetate,1-octene, Ethyl butanoate, and citral. These substances will serve as marker compounds for the identification ofSchisandra chinensisprocessed by different methods in the future.
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ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Hanlong Yan,Guo Zhao,Wei Lu,Can Hu,Xiaochan Wang,Gang Liu,Ning Shi,Nguyen Thi Dieu Thuy,Litao Zhang
This study developed a flexible and wearable paper-based chemoresistive sensor (FWPCS) by modifying a SWCNT-PdNP-polystyrene microsphere (SPPM) composite (SPPM/FWPCS) for the low-cost and online determination of fruit ripeness and corruption. A new method for the batch and low-cost fabrication of SPPM/FWPCSs based on laser direct writing was proposed. The sensing mechanism of FWPCS relies on the electron depletion layer in the sensing composite created by the Schottky barriers among SWCNTs, PdNPs, and the adsorbed oxygen, along with the construction of O 2 − . When the SPPM sensing film is exposed to ethylene, trapped electrons are released into the conduction band through oxidation and cleavage of ethylene, causing a decrease in resistance. The properties and morphology of the synthesized SPPM composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy . Additionally, the key parameters for the fabrication of SPPMs/FWPCS related to the sensing performance were optimized. The concentration of C 2 H 4 can be detected down to 100 ppb using the SPPMs/FWPCS at 25 °C. Finally, the real-time determination of banana ripeness and corruption verified the feasibility of the sensor, indicating that the SPPMs/FWPCS has prospects in monitoring fruit ripeness and corruption during storage and transportation.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2019
·
IF 2.983
Jia Xu,Yuanyuan Zhai,Li Feng,Tong Xie,Weifeng Yao,Jinjun Shan,Li Zhang
Energy synthesis in aerobic organisms relies on two major metabolic pathways, i.e. tricarboxylic acid (TCA) cycle and glycolysis, the metabolites of which are highly affected by many diseases. Cells are the basic unit of the organism and have independent, ordered and self-controlled metabolic systems. Therefore, it is necessary to quantify intracellular metabolites in TCA cycle and glycolysis. In this study, we established a repeatable gas chromatography-tandem mass spectrometry (GC–MS/MS) method with selected reaction monitoring (SRM) mode for simultaneous quantification of several primary metabolites in these two pathways, including glucose, 3-phosphoglycerate, phosphoenolpyruvate (PEP), pyruvate, lactate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. There are many solvents to extract the metabolites in these two pathways, however, which one is more effective still remains unclear. Sample pretreatment was optimized for solvent types and volumes to advance the extraction efficiency of metabolites. 500 μL of 75% methanol-methyl tert-butyl ether (MTBE) was finally selected for the extraction of targeted metabolites in cells due to its highest extraction efficiency. Activated carbon as an effective adsorbent was successfully applied to the removal of endogenous targeted metabolites in cells for getting the analyte-free surrogate matrices. A series of methodological studies verified the validity of this optimized approach which was applied to quantify and compare the targeted metabolites in three common hepatic cells. The developed GC–MS/MS method provided a better way to determine the metabolites of energy metabolism in cellular metabolomics, facilitating the application of targeted quantification metabolomics to precisely discover the metabolic alterations.
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