JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Dandan Li,Man He,Beibei Chen,Bin Hu
Magnetic porous organic polymers (MOPs) were synthesized by a simple azo reaction, with 1,3,5-tris (4-aminophenoxy) benzene and 1,3,5-trihydroxybenzene as the monomers, and Fe 3 O 4 @SiO 2 as the core. The preparation process was mild, green and environmental-friendly, avoiding the use of high temperature, metal catalysis and harmful organic reagent. The obtained MOPs were characterized in terms of morphology, pore structure, and magnetism; they exhibited high surface area, good stability/dispersibility, and excellent extraction performance for interest triazole fungicides (TFs). With the prepared MOPs as adsorbent, a method of magnetic solid phase extraction-gas chromatography-flame ionization detection (MSPE-GC-FID) was proposed for the analysis of target TFs in vegetables. After the vegetable samples were chopped and homogenized, acetonitrile was added for ultrasonic extraction, and the extract was diluted for subsequent MSPE process. Different operating conditions affecting the extraction efficiency of TFs, such as extraction time, pH, ionic strength, adsorbent dosage, and volume of sample as well as eluent were carefully optimized. Under the optimized experimental conditions, quantitative extraction could be achieved for target TFs (extraction efficiency of 84.5–90.3%), and the limits of detection were in the rage of 0.12–0.19 μg/L, which is the lowest among the reported GC-FID methods for target TFs presently. The linear range of the method for five TFs was 0.5–200 μg/L with the reproducibility of 2.6–6.8% (n = 7, c = 2 μg/L). The method was assessed by the analysis of target TFs in vegetables, and the recoveries for the spiked cucumber and cabbage were 86.9–117% and 84.7–114% (spiking levels of 80, 400 and 800 μg/kg), respectively, indicating that the matrix effect was negligible in the proposed MSPE procedure. The results show that the developed method of MSPE-GC-FID with MOPs as adsorbent is efficient for the analysis of trace TFs in vegetables.
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JOURNAL OF FOOD SCIENCE
·
2024
·Vol. 89
·期 12
·9198-9213
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IF 3.2
Lijuan Du,Yanping Ye,Jinliang Shao,Yutong Wang,Guolei Zhu,Hua Jiang,Hongcheng Liu,Zhenhuan Liu
The assessment of aroma plays a crucial role in determining the characteristics and quality of Pu-erh tea. The volatile compounds present in Pu-erh raw tea sourced from five regions in Yunnan Province have been studied using gas chromatography-mass spectrometry (GC-MS) in conjunction with headspace solid phase microextraction (HS-SPME). A total of 69 aroma-active compounds were identified, with alcohols, ketones, and aldehydes being the predominant component types. Furthermore, notable variations were observed among four pairs of volatile terpenoid enantiomers. Significant discrimination was achieved using orthogonal partial least squares discrimination analysis ( R ( x 2 ) = 0.926, R ( y 2 ) = 0.843, Q 2 = 0.501). Moreover, 33 important differential compounds were identified based on variable importance in the projection values (VIP > 1.0) and one-way ANOVA analysis ( p < 0.05). Subsequently, a KEGG pathway analysis was conducted, revealing enrichment pathways primarily focused on the mevalonate pathway, steroid biosynthesis, and fatty acid biosynthesis. Ultimately, the key volatile compounds and major aroma-contributing compounds were successfully identified.
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ANALYTICAL LETTERS
·
2024
·
IF 1.6
Cheng Qian,Pei Zhang,Chao Nie,Hui Jiang,Linghu Cai,Xiangyu Chen,Minghua Liu
Green MgO-based banana peel activated carbon (MgO-BPAC) with distinctive pore structure features was synthesized with magnesium nitrate as the template and activator. A novel solid-phase microextraction (SPME) fiber was prepared by fixing MgO-BPAC on the surface of a stainless-steel wire using silicone sealant. The fiber was coupled with gas chromatography-mass spectrometry (GC-MS) for headspace-solid phase microextraction-GC-MS (HS-SPME-GC-MS) for polycyclic aromatic hydrocarbons (PAHs). The laboratory-constructed fiber showed good extraction efficiency for naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, and anthracene and the corresponding analytical parameters were determined. The method provided low detection limits (0.86–2.12 ng/L) with satisfactory replicate extractions of one fiber (relative standard deviations ≤ 10.30%) and fiber to fiber reproducibility (relative standard deviations ≤ 13.92%). To validate the performance of the homemade fibers, this approach was used for the determination of the PAHs (0.05 μg/L) in spiked environmental water samples and good recoveries (92.67%–114.45%) were obtained. This study introduces a biocarbon material as a functional fiber coating component which adsorbs aromatic constituents through hydrophobic interactions.
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Food Science and Human Wellness
·
2024
·
IF 5.6
Yufei Liu,Xiaonian Cao,Zhilei Zhou,Qingxi Ren,Zhongwei Ji,Min Gong,Yuezheng Xu,Weibiao Zhou,Shuguang Chen,Jian Mao
Higher alcohols are key factors affecting sensory quality and post-drinking comfort of alcoholic beverages. A strategy combining solid-phase extraction and gas chromatography-mass spectrometry (SPE-GC-MS) was established to analyze the metabolism pattern of higher alcohols in rat plasma after gavage of 4 common alcoholic beverages including huangjiu, baijiu, wine and brandy. 7 mL of dichloromethane was determined as the optimal extraction condition, and 8 higher alcohols were precisely quantified with detection limits of 1.82−11.65 μg/L, recoveries of 89.07 %−110.89 % and fine repeatability. The fastest absorption and elimination rates of plasma total higher alcohols were observed in baijiu and huangjiu group, respectively, and the highest peak concentration was found in brandy group. Additionally, the metabolic rate of plasma isoamyl alcohol in huangjiu group was faster than that in wine group at the same intragastric administration dosage. This study may provide potential insight for evaluation of alcoholic beverage quality.
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ACS Catalysis
·
2025
·
IF 13.1
Shengpeng Mo,Shuangde Li,Jiangjing Zhou,Xin Zhao,Huimin Zhao,Xiaobin Zhou,Yinming Fan,Zongqiang Zhu,Bing Li,Qinglin Xie,Wenzhe Si,Yunfa Chen,Daiqi Ye,Junhua Li
A concentrated solar reaction device has been designed for the solar-driven photothermal CO2 reverse water–gas shift reaction, in which solar-to-chemical conversion efficiency would be up to 26% via a concentrated solar panel. Meanwhile, a special photothermal Ni–C–In catalyst (Ni/C–In2O3) with interstitial C, the In3Ni2 intermetallic compound, and disordered Ni clusters has been synthesized. As a result, the SO2-tolerant Ni/C–In2O3 catalyst exhibits an outstanding solar-driven photothermal catalytic performance (near thermodynamic limitation) with 100% CO selectivity and a 20.96 mmol gcat–1 h–1 CO production rate for solar-driven CO2 hydrogenation under concentrated solar irradiation (around 1521.9 mW/cm2) even sunlight without external heating. The incorporation of interstitial C and exposed Ni clusters in the Ni–C–In intermetallic catalyst could strengthen intensive solar light absorption. Moreover, quasi in situ XPS and DFT theoretical calculation results validate that asymmetric interaction between interstitial C and the Ni-cluster not only effectually regulates the electronic structure of the Ni–C–In intermetallic catalyst but also greatly optimizes the activation of H2 and CO2 molecules and the energy barriers of key reaction dynamics (HCOO* formation and dehydrogenation) in the RWGS reaction. Accordingly, this study provides a promising strategy for the electronic structure modification of photothermal functional catalysts with C modification to boost CO2 hydrogenation, putting forward an important step toward practical solar-to-fuel production with concentrated natural sunlight.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Weiqian Liang,Juntao Wang,Xiaohuan Zang,Wenhuan Dong,Chun Wang,Zhi Wang
In this work, a barley husk biomaterial was successfully carbonized by hydrothermal method. The carbon had a high specific surface area and good stability. It was coated onto a stainless steel wire through sol-gel technique to prepare a solid-phase microextraction fiber for the extraction of trace levels of twelve pesticides (tsumacide, fenobucarb, indoxacarb, diethofencarb, thimet, terbufos, malathion, thiamethoxam, imidacloprid, buprofezin, acetamiprid, thiamethoxam) from vegetable samples prior to gas chromatography–mass spectrometric (GC–MS) detection. The main experimental parameters that could influence the extraction efficiency such as extraction time, extraction temperature, sample pH, sample salinity, stirring rate, desorption temperature and desorption time, were investigated. Under the optimized conditions, the linearity was observed in the range of 0.2–75.0 μg kg −1 for tomato samples, and 0.3–60.0 μg kg −1 for cucumber samples, with the correlation coefficients ( r ) ranging from 0.9959 to 0.9983. The limits of detection of the method were 0.01–0.05 μg kg −1 for tomato samples, and 0.03–0.10 μg kg −1 for cucumber samples. The recoveries of the analytes for the method from spiked samples were in the range of 76%–104%, and the precision, expressed as the relative standard deviations, was less than 12%.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2016
·
IF 5.393
Yao Lin,Yuan Yang,Yuxuan Li,Lu Yang,Xiandeng Hou,Xinbin Feng,Chengbin Zheng
Rice consumption is a primary pathway for human methylmercury (MeHg) exposure in inland mercury mining areas of Asia. In addition, the use of iodomethane, a common fumigant that significantly accelerates the methylation of mercury in soil under sunlight, could increase the MeHg exposure from rice. Conventional hyphenated techniques used for mercury speciation analysis are usually too costly for most developing countries. Consequently, there is an increased interest in the development of sensitive and inexpensive methods for the speciation of mercury in rice. In this work, gas chromatography (GC) coupled to dielectric barrier discharge optical emission spectrometry (DBD-OES) was developed for the speciation analysis of mercury in rice. Prior to GC-DBD-OES analysis, mercury species were derivatized to their volatile species with NaBPh4 and preconcentrated by headspace solid phase microextraction using porous carbons. Limits of detection of 0.5 μg kg–1 (0.16 ng), 0.75 μg kg–1 (0.24 ng), and 1.0 μg kg–1 (0.34 ng) were obtained for Hg2+, CH3Hg+, and CH3CH2Hg+, respectively, with relative standard deviations (RSDs) better than 5.2% and 6.8% for one fiber or fiber-to-fiber mode, respectively. Recoveries of 90–105% were obtained for the rice samples, demonstrating the applicability of the proposed technique. Owing to the small size, low power, and low gas consumption of DBD-OES as well as efficient extraction of mercury species by porous carbons headspace solid phase micro-extraction, the proposed technique provides several advantages including compactness, cost-effectiveness, and potential to couple with miniature GC to accomplish the field speciation of mercury in rice compared to conventional hyphenated techniques.
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RSC Advances
·
2016
·Vol. 6
·期 78
·74944-74956
·
IF 3.289
Yang Li,Huitao Ban,Mingfei Jiao,Mujie Yang
We report a facile method for the in situ growth of vertically aligned SnO2 nanosheets on a substrate, which involved the hydrothermal treatment of the substrate covered with electrospun nanofibers of poly(vinyl butyral) containing SnCl2 at low temperatures and free of additives. The formation mechanism of nanostructured SnO2 has been explored. Gas sensors based on the composites of SnO2 nanosheets and polyaniline were prepared by vapor phase polymerization of aniline or the dip coating with water-processable polyaniline, and revealed good contact between the sensing films and underlying electrode. The nanocomposite sensors demonstrate very high response magnitude toward NH3 (relative resistance change of ∼3700% towards 10.7 ppm of NH3), ultra-low detection limit (∼46 ppb), good sensing repeatability and excellent selectivity at room temperature. Investigations on the gas sensing mechanism of the nanocomposite suggest that the establishment of the p/n heterojunction at the interface of p-type PANI and n-type SnO2 play an important role in enhancing the response magnitude of the nanocomposite. The method could provide new solutions for the direct fabrication of optoelectronic and electrochemical devices based on nanostructured metal oxides and their composites.
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Food Analytical Methods
·
2014
·Vol. 7
·期 9
·1763-1769
·
IF 1.802
Zhang Yanping,Ma Xiaoguo,Fan Yingming
A method for rapid and sensitive determination of melamine in aquatic products by gas chromatography–mass spectrometry with microwave-assisted derivatization was proposed in this paper. Melamine was extracted from aquatic product samples using methanol, and the extract was cleaned with a mixed-mode cationic exchange solid phase extraction column. After elution with 5 % ammonia–methanol solution and drying with nitrogen, the residue was derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide containing 1 % trimethylchlorosilane under microwave irradiation for 1 min with a power of 420 W, then detected with gas chromatography–mass spectrometry, and quantified by the external standard method. Some important parameters such as extraction solvent, microwave irradiation power and time, and derivatization reagent volume were investigated and optimized. The results showed that methanol could effectively extracted melamine from aquatic products as well as precipitated the protein in samples. Under the optimum conditions, the detection limit for melamine was as low as 0.006 mg/kg, and the linear range was from 0.02 to 50 mg/kg with a correlation coefficient of 0.9997. The proposed method was applied to the analysis of melamine in aquatic products (fish, shrimp, clam, and winkle), and the recovery for melamine was 89.65–105.16 % with relative standard deviation of 3.0–6.0 %.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2013
·
IF 2.906
Qin Zhao,Qian Lu,Qiong-Wei Yu,Yu-Qi Feng
This article presents a novel application of dispersive microextraction based on “magnetic water” (m-water) for the purification of organophosphorus pesticides (methamidophos, omethoate, monocrotophos) from cold-pressed vegetable oils. In the present study, a trace amount of water (extractant) was adsorbed on bare Fe3O4 by hydrophilic interaction to form m-water. Rapid extraction can be achieved while the m-water is dispersed in the sample solution with the aid of a vigorous vortex. After extraction, the analyte-adsorbed m-water can be readily isolated from the sample solution by a magnet, which could greatly simplify the operation and reduce the whole pretreatment time. Several parameters affecting the extraction efficiency were investigated, and under the optimized conditions, a simple and effective method for pesticide analysis was established by coupling with gas chromatography/mass spectrometry (GC/MS). The linearity range of the proposed method was 2–100 ng/g with satisfactory correlation coefficients (R) of 0.9997–0.9998, and the limits of quantification (LOQ) for the target compounds were in the range of 0.70–1.27 ng/g. In addition, the reproducibility was obtained by evaluating the intra- and interday precisions with relative standard deviations (RSDs) less than 7.2% and 6.5%, respectively. Finally, the established “magnetic water” microextraction method was successfully applied for the determination of pesticide residues in several kinds of cold-pressed vegetable oils.
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JOURNAL OF CHROMATOGRAPHY A
·
2014
·
IF 4.258
Hongyuan Yan,Chen Yang,Yunyun Sun,Kyung Ho Row
A new type of ionic liquid molecularly imprinted polymers (IL–MIPs) synthesized by precipitation polymerization using 1-allyl-3-methylimidazolium bromide as an auxiliary solvent and α-chloro-dichlorodiphenyltrichloroethane (α-chloro-DDT) as the template was applied as a selective sorbent of minimized pipette tip-solid-phase extraction (PT-SPE) for rapid isolation and extraction of dicofol (DCF) from celery samples. The pretreatment procedure of celery samples involved only 2.0 mg of IL–MIPs, 0.8 mL of acetonitrile–water (ACN–H 2 O; 1:1, v/v) (washing solvent), and 1.0 mL of acetone–10% acetic acid (HOAc) (elution solvent). Compared with molecularly imprinted polymers (MIPs), ionic liquid–non-imprinted polymers (IL–NIPs) and conventional sorbents such as C 18 , Si, NH 2 , and Al 2 O 3 –N, IL–MIPs showed higher adsorption and purification capacity to DCF in aqueous solution. Good linearity for DCF was observed in the range from 2.3 to 232.5 ng g −1 ( r 2 = 0.9995). The average recoveries at three spiking levels ranged from 86.6% to 101.9% with relative standard deviations (RSDs) of ≤6.5% ( n = 3). The presented IL–MIPs–PT-SPE–GC/ECD method combines the advantages of MIPs, IL, and PT-SPE, and can be used in aqueous conditions with high affinity and selectivity to analytes of complex samples.
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Frontiers in Microbiology
·
2024
·
IF 4
Xinwen Dong,Yaguang Su,Zheng Luo,Cuiying Li,Jie Gao,Xiaofeng Han,Sanqiao Yao,Weidong Wu,Linqiang Tian,Yichun Bai,Guizhi Wang,Wenjie Ren
Background: Dysbiosis of gut microbiota (GM) is intricately linked with cognitive impairment and the incidence of traumatic brain injury (TBI) in both animal models and human subjects. However, there is limited understanding of the impact and mechanisms of fecal microbiota transplantation (FMT) on brain and gut barrier function in the treatment of TBI induced by gas explosion (GE).Methods: We have employed FMT technology to establish models of gut microbiota dysbiosis in male rats, and subsequently conducted non-targeted metabolomics and microbiota diversity analysis to explore the bacteria with potential functional roles.Results: Hematoxylin–eosin and transmission electron microscopy revealed that GE induced significant pathological damage and inflammation responses, as well as varying degrees of mitochondrial impairment in neuronal cells in the brains of rats, which was associated with cognitive decline. Furthermore, GE markedly elevated the levels of regulatory T cell (Tregs)-related factors interleukin-10, programmed death 1, and fork head box protein P3 in the brains of rats. Similar changes in these indicators were also observed in the colon; however, these alterations were reversed upon transfer of normal flora into the GE-exposed rats. Combined microbiome and metabolome analysis indicated up-regulation of Clostridium_T and Allobaculum, along with activation of fatty acid biosynthesis after FMT. Correlation network analysis indirectly suggested a causal relationship between FMT and alleviation of GE-induced TBI. FMT improved intestinal structure and up-regulated expression of tight junction proteins Claudin-1, Occludin, and ZO-1, potentially contributing to its protective effects on both brain and gut.Conclusion: Transplantation of gut microbiota from healthy rats significantly enhanced cognitive function in male rats with traumatic brain injury caused by a gas explosion, through the modulation of gut microbiome composition and the improvement of both gut and brain barrier integrity via the gut-brain axis. These findings may offer a scientific foundation for potential clinical interventions targeting gas explosion-induced TBI using FMT.
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