ANALYTICA CHIMICA ACTA
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2021
·
IF 6.558
Xiao-Xue Jiang,Li-Qing Yu,Yue-Na Sun,Yuan Li,Hui-Min Li,Yun-Kai Lv
In this work, we reported the preparation of the hollow zeolitic imidazolate framework-7 (ZIF-7) via etching ZIF-7 with tannic acid , and further fabricated the hollow ZIF-7 coated fiber for the solid phase microextraction (SPME) of the five volatile biomarkers (acetone, isopropanol, hexanal , hexanol and decanal) generated from breast cancer cell lines. The hollow structure not only endowed higher extraction performance for the SPME of analytes, but also improved the diffusion rate of the analytes inside the hollow ZIF-7. Under the optimal conditions, the hollow ZIF-7 coated fiber offered high extraction capacity (25–153 mg g −1 ) and enhancement factors (EFs, 2023–11250) for the five biomarkers, good linearity (R 2 > 0.9918) of acetone and isopropanol (2.5–500 μg L −1 ) and hexanol, hexanal, and decanal (1.0–100 μg L −1 ), low limits of detection (S/N = 3) of 0.07–0.53 μg L −1 and the limit of quantifications (LOQs, S/N = 10) of 0.23–1.76 μg L −1 . The precisions (RSDs, %) for intra-day (n = 6), inter-day (n = 5) and fiber-to-fiber (n = 6) were 2.8–7.5%, 4.3–8.5%, and 4.2–14.6%, respectively. The high EFs of the hollow ZIF-7 coated fiber for the five biomarkers resulted from the integrated effects of the large surface area, the unique porous structure, hydrophobic interaction, gate-opening effect, and enhanced properties after etching including faster mass transport, multiple active components, and more exposed active sites. The fabricated hollow ZIF-7 coated fiber lasted at least 140 cycles of extraction/desorption/aging without obvious decrease of extraction ability and no change of crystal structure. Finally, the hollow ZIF-7 coated fiber combined with GC-FID had been successfully used to detect the five biomarkers in the headspace gas of human breast cancer cell lines (MDA-MB-231) and normal mammary cell lines (CCD-1095Sk) with the recoveries of 84–105%. These results revealed the prospect of hollow MOFs as efficient adsorbents for sample pretreatment .
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LWT-FOOD SCIENCE AND TECHNOLOGY
·
2021
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IF 4.952
Shan-Shan Zhang,Sen Guo,Zhao-Jing Zheng,Shao-Jing Liu,Yu-Fei Hou,Chi-Tang Ho,Nai-Sheng Bai
Volatiles in four Allium tenuissimum flower samples were detected and characterized by headspace-gas chromatography-olfactometry-mass spectrometry, and odor activity values. The key aroma compounds were determined by combining the sensory analysis with the omission and recombination experiments. The results illustrated that a total of 36 volatiles were identified and divided into six types, including sulfur-containing compounds, aldehydes, alcohols, ketones, nitrogen-containing compounds, and others. The sulfur-containing compounds and aldehydes were the two most abundant compounds in A. tenuissimum flower. The volatiles were quantified through authentic reference compounds, and the contents of these compounds in four A. tenuissimum flower samples were obtained. Five key aroma compounds of A. tenuissimum flower were confirmed as dimethyl disulfide, dimethyl trisulfide, linalool, 2-methylbutanal, and nonanal. Among these, the predominant compounds dimethyl disulfide and dimethyl trisulfide having strong onion and sulfur aroma, significantly contributed to the aroma of A. tenuissimum flower. The main aroma profiles of A. tenuissimum flower were onion, sulfur, flower, green and burnt. The closer the geographical location and environment of A. tenuissimum flower growth are, the more similar their chemical composition.
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TALANTA
·
2021
·
IF 6.057
Zhenyu Lu,Xiaotian Lu,Ling Xia,Yanhui Zhong,Gongke Li,Yufei Hu
In this work, a catalytic material of cobalt doped nitrogenous porous carbon (Co/NPC) was fabricated from covalent organic frameworks (COFs) and cobalt ion via directly carbonization . Attribute to the excellent selective catalytic performance towards n -hexane, Co/NPC was employed in cataluminescence (CTL) for rapid and sensitive determination of n -hexane. Moreover, the detection conditions of CTL were evaluated, including temperature, flow rate and detecting wavelength. Under optimized conditions, a good linear relation between signal intensity of CTL and n -hexane concentration was obtained in the linear range of 0.4–250.0 mg/L and the limit of detection (LOD, S/N = 3) was 0.13 mg/L. Furthermore, the Co/NPC based CTL sensor was successfully applied to the determination of n -hexane in edible oil samples with the recoveries in the range of 92.0%–104.0%. The method comparison results of GC/MS and CTL on real sample analysis further proved the accuracy of the developed Co/NPC based CTL method. Additionally, the possible catalytic mechanism of n -hexane on the surface of Co/NPC was investigated, assisting by GC/MS on intermediation products identification. Overall, the Co/NPC based CTL sensor has been confirmed excellent performance in the n -hexane determination, which revealing extensive application in rapid residual n -hexane analysis in edible oil .
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JOURNAL OF AOAC INTERNATIONAL
·
2020
·Vol. 104
·期 3
·712-718
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IF 1.51
Wei Min,Zheng Feng,Song Xuyan,Li Ran,Pan Xi,Guo Guoning,Yu Qiongwei,Feng Yuqi
BackgroundSome volatile compounds in mouthpiece cigarette adhesive emit irritating odors and affect the taste of smoking cigarettes. Therefore, it is necessary to monitor the volatile compounds in mouthpiece cigarette adhesive.ObjectivesA rapid and simple analytical method of volatile compounds in mouthpiece cigarette adhesive was established.MethodsIn this study, headspace (HS) injection coupled with GC–MS was utilized for qualitative and quantitative analysis. Initially, the volatile compounds in mouthpiece cigarette adhesives were detected by HS-GC–MS, followed by spectrum library retrieval. The detected compounds with the similarity to a spectrum library of more than 85% were further identified by comparing the retention time and mass spectra of the detected volatile compounds and those of the corresponding standard samples. The quantitative analysis of nine identified volatile compounds was performed.ResultsEleven volatile compounds in the mouthpiece cigarette adhesive were accurately identified. The quantitative analytical method of nine volatile compounds in mouthpiece cigarette adhesive was validated to have good linearities (R2 > 0.9932) within the range of 20–5000 ng/g. The detection limits of 9 compounds were within the range of 3.1–147.7 ng/g. The intra- and inter-day relative standard deviations were less than 19.8%. The recoveries of these 9 compounds spiked into mouthpiece cigarette adhesive were 68.1–108.3%.ConclusionsThe proposed method is rapid, simple, and accurate for qualitative and quantitative analysis of volatile compounds in the mouthpiece cigarette adhesive.HighlightsThe developed analytical method is expected to be used to monitor volatile compounds in various adhesives.
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TALANTA
·
2020
·
IF 5.339
Xue Li,Yuan-Yuan Cui,Cheng-Xiong Yang
Microporous organic networks (MONs) have shown great promise in separation science recently. Exploring novel, simple and convenient strategy to fabricate MONs coated capillary columns for gas chromatography (GC) still remains challenging but desirable for the development of MONs in chromatographic separation. To extend the potential application of MONs in separation science and to further develop novel method for the fabrication of MONs-based capillary columns, here we demonstrate a novel covalent coupling strategy to fabricate uniform MONs bonded capillary columns for GC separation of position isomers and hydrocarbons. The bare capillary column was firstly modified with (3-bromopropyl)trimethoxysilane to provide bromine sites for coupling with alkynyl monomers . The amino- and hydroxyl-functionalized MONs (MON-NH 2 and MON-OH) were then directly grown onto the inner wall of the brominated capillary columns via the covalent coupling between bromine and alkynyl groups. The uniform MON-NH 2 and MON-OH bonded capillary columns were obtained and showed good resolution for GC separation of dichlorobenzene , chlorotoluene, bromotoluene, and propylbenzene position isomers and many other hydrocarbons including linear alkanes, alkylbenzenes , pinene isomers, cyclohexane and benzene, ketones and aldehydes. The MONs bonded capillary columns also owned good lifetime and precision for dichlorobenzene isomers with the relative standard deviations (RSDs) of 0.2–0.3%, 1.2–2.1%, and 1.7–2.5% for retention time, peak height and peak area, respectively. In addition, the fabricated MON-NH 2 and MON-OH bonded capillary columns offered better resolution than commercial InertCap-1, InertCap-5, InertCap-1701 and InertCap-WAX capillary columns for the separation of chlorotoluene and bromotoluene position isomers. These results revealed the feasibility of covalent coupling strategy to fabricate MONs-based stationary phases in GC, highlighting the potential of MONs in separation science.
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POULTRY SCIENCE
·
2020
·
IF 2.659
Wensheng Yao,Yingxuan Cai,Dengyong Liu,Zhinan Zhao,Zhenghao Zhang,Shuangyu Ma,Mingcheng Zhang,Hao Zhang
This article presents investigation of the flavor profile on 5 different regional Chinese smoked chicken samples using gas chromatography−ion mobility spectrometry analysis methods. Five batches of samples were obtained over the course of 6 mo. A total of 34 flavor substances were identified in the 5 smoked chicken samples, including 10 aldehydes, 7 alcohols, 4 ketones, 2 hydrocarbons, 3 heterocyclic compounds, 4 esters, 2 ethers, and 2 phenolic compounds. The whole spectral fingerprint visually displayed flavor differences and relations in 5 types of smoked chicken with local characteristics. Moreover, the orthogonal projections to latent structures discriminant analysis model revealed that these samples could be separately classified into 5 groups. Multivariate statistical analysis showed that 20 chemicals with higher Variable Importance for the Projection values were the key contributors to the differences of flavor in these 5 kinds of smoked chicken. N-nonanal, heptanal, n-nonanal, heptanal, furfurol, and hexanal were the main common flavor compounds in the 5 types of Chinese smoked chicken, whereas linalool, alpha-terpineol, 1,8-cineole, and anethole were the main characteristic flavor compounds of Goubangzi chicken (No. 1); gamma-butyrolactone, 2-acetylfuran, 2-methoxyphenol, 2-acetylpyrrole, and limonene were determined as the key flavor compounds of Liaocheng chicken (No. 2); the concentration of octanal and n-nonanal was higher in Tangqiao chicken (No. 3); butyl acetate was the key contributor to the flavor compounds of Jinshan chicken (No. 4). 2-Heptanone and 2-pentylfuran had a high correlation with Zhuozishan chicken (No. 5). The different raw materials and ingredients used, especially the method of preparation and cultural differences, in different regions of the country in China were the main reasons leading to the similarities and differences of volatile compounds in the 5 kinds of Chinese traditional smoked chicken.
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COMPUTERS AND ELECTRONICS IN AGRICULTURE
·
2020
·
IF 3.858
Chengyu Zheng,Zhenhe Wang,Jing Zhang,Jun Wang,Jianli Zhong,Yongwei Wang
Platycladus orientalis plants in China are experiencing a serious problem with wood-boring beetles, but conventional physical detection methods cannot perform well due to hidden larvae and less obvious symptoms in the early infestation. In this study, the volatile organic compounds (VOCs) of P. orientalis were investigated using gas chromatography-ion mobility spectrometry (GC-IMS) to identify its internal infestation. An image-based evaluation method of the degree of internal wood damage was proposed, the principal component analysis (PCA) based on specific markers was applied for natural clustering of samples, and unsupervised learning approaches based on specific markers and automatically located peaks were used to create predictive models for sample classification. The results showed that the herbivore-induced plant volatiles (HIPVs) of P. orientalis samples had two main characteristics compared with undamaged plants. One was the emergence of several compounds such as C 3 -C 6 ketones, aldehydes, and alcohols, while the other was the obvious content variation of several monoterpenes and their derivatives. The classification models based on specific markers and automatically located peaks could correctly classify at least 89.5% and 87.9% of the samples, respectively. In a word, these results proved that GC-IMS based approaches combined with different feature extraction methods have the potential to identify the internal infestation of wood-boring beetles in P. orientalis .
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Peng Chen,Xie Liu,Zhihao Lu,Liang Jin,Lankun Cai,Lehua Zhang,Hualin Wang,Ying Yan
Attention is drawn to the freezing method for separating organic contaminants from industrial wastewater and simultaneously recovering valuable materials, but the mechanism regarding functional group of organic contaminants how affect ice purity remains unclear. In this work, four types of organics, including hexane , hexanoic acid, N-hexanol and N-hexanal, with various oxygen functional groups were selected as organic contaminants and studied to be separated from aqueous solutions by the suspension freezing method. Experimental results revealed that their separation efficiencies were 67.07%, 87.75%, 94.71% and 95.32%, respectively, after freezing 30 min at 200 rpm and −0.9 °C. The presented theoretical work reveals that hexane, as a non-polar organic contaminant without function group, unable to form hydrogen bonds with water clusters, making it more readily to precipitate and stick on ice surface during freezing, which significantly increased ice impurities with the lowest separation efficiency. Presence of functional group promotes organics to solute in concentrate via forming H-bond with water clusters, and thus improves ice purity by avoiding of precipitation. Hexanoic acid with the largest absorption energy with ice crystal tend to adsorb on ice surface but not stay in concentrate and showed the highest ice impurity corresponding to lowest separation efficiency. This work provides new sight for understanding declination of ice purity and separation efficiency caused by functional group of organic contaminants during freezing.
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FOOD RESEARCH INTERNATIONAL
·
2020
·
IF 4.972
Chao Wang,Zhongrong He,Chenxia Zhang,Liping Du,Dongguang Xiao,Yongquan Xu
The objective of this study was to identify the released behavior of odor-active compounds of Pu-erh tea during the water-boiling extraction, as well as to explore the feasibility of aroma recovery using absorption oils. The behavior of odor-active compounds was identified by using piecewise recovered condensed water combined with sensory, GC-O, and GC–MS analysis. The power-function type kinetic model was the model that best fitted odor intensities, alcohols, methoxy-phenolics, esters, aldehydes, ketones, and total compounds of condensed water. The sensory quality of the condensed water was the best when 16% of added water was evaporated. Six absorption oils were evaluated, and paraffin oil (35 cSt) performed the best in terms of both absorption efficiency and sensory quality of the essential oil. Under the optimized conditions, the absorption and recovery efficiency of odor compounds reached 54.49% and 39.52%, respectively. The alcohols, aldehydes, and methoxy-phenolics exhibited higher absorption and recovery efficiency.
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JOURNAL OF SEPARATION SCIENCE
·
2020
·Vol. 43
·期 12
·2401-2408
·
IF 2.878
Xiaoji Cao,Mei Fang,Danqi Dong,Beibei Ye,Jiahui Xu,Xuemin Ye,Weimin Mo
A dispersive liquid–liquid extraction based on Pickering emulsion stabilized with ferroferric oxide grafted nitrogen-doped graphitized carbon black has been developed to simultaneously determine seven aldehydes in environmental water samples, in combination with pentafluorobenzyl hydroxylamine precolumn derivatization gas chromatography–tandem mass spectrometry. The nitrogen-doped graphitized carbon was prepared from dicyandiamide waste residue with a simple acid wash process. The effects of magnetic emulsifier amount, extraction time, solution pH, and oil/water volume ratio on the formation of magnetically responsive Pickering emulsion and the extraction efficiency of the proposed dispersive liquid–liquid extraction were also investigated. Under the optimized conditions, satisfactory linearities were obtained for all aldehydes with correlation coefficients larger than 0.9984. The limits of detection and quantitation of seven aldehydes were in the range of 17.3–30.1 ng/L and 54.3–103.4 ng/L, respectively, with intra- and interday relative standard deviations less than 8.6%. The mean recoveries at three spiked levels ranged from 70.0 to 101.4%. With the Pickering emulsion as a “minimized extractor”, the extraction was accomplished within 5 min. After extraction, the magnetic disperser could be recovered for reuse at least five times by an external magnetic field. The proposed method was demonstrated to be feasible, simple, and economic for the trace analysis of the aldehydes in environmental water samples.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Zhenhe Wang,Wei Chen,Shuang Gu,Jun Wang,Yongwei Wang
Trunk borers infestation is difficult to detect because larvae always mine inside trees. However, plants volatile organic compounds (PVOCs) usually change markedly after pests damage which provide us an opportunity to identify trunk borers infestation. Herein, a four-element quartz crystal microbalance (QCM) gas sensor array based on molecularly imprinted polymers (MIPs) was reported for the discrimination of Semanotus bifasciatus (Motschulsky) and Phloeosinus aubei Perris (Coleoptera: Scolytidae) infested Platycladus orientalis (L.) Franco trunks. MIPs were prepared using the methacrylic acid (MAA) polymer matrix and four characteristic PVOCs (α-pinene, β-phellandrene, 3-carene and cis-thujopsene) as templates molecules, repectively. The amounts of MIPs dropped on the QCM chips were investigated and optimized according to the sensitivities and response times. Finally, the sensor array was applied to detect PVOCs of P. orientalis trunks with S. bifasciatus and P. aubei infestation, and the response matrix were processed with principal component analysis (PCA) and linear discrimination analysis (LDA) for visualization, and further discrimination was performed by k-nearest neighbor (KNN), probabilistic neural network (PNN) and support vector machine (SVM). SVM exhibited satisfying identification accuracy rates in both calibration set (97.62 %) and validation set (93.75 %). This study may contribute to gas sensor arrays development in areas of pest control and forest protection.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Huimin Zhang,Dan Wu,Qilin Huang,Zhiyu Liu,Xiaogang Luo,Shanbai Xiong,Tao Yin
Yeast β-glucan (YG) adsorbs off-odor in silver carp mince due to its more porous structure. To explore adsorption behavior and mechanism, adsorption kinetics and thermodynamics of YG for 3 off-odor compounds (hexanal, 1-octen-3-ol and nonanal) were investigated by pseudo-first/second-order models and isothermal equations (Langmuir, Freundlich and Redlich-Peterson). Kinetic experiments indicated adsorption process followed pseudo-first-order model. Adsorption isotherms indicated 3 off-odors could easily be adsorbed by YG and adsorption capacity was in the order of 1-octene-3-ol > hexanal > nonanal . Thermodynamic result suggested adsorption of 3 off-odors by YG was endothermic and spontaneous, and was driven predominantly by physisorption and hydrophobic interaction. Consequently, the contents of 3 off-odors that released from mince/YG complex decreased by 22.8%, 29.9%, and 24.5% ( p < 0.05), respectively, compared with those from mince without YG. Therefore, the addition of YG enhanced the binding capability to off-odors, thus reducing the release of off-odor from silver carp mince.
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危险品化学品经营许可证（带存储）