The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
To establish a new GC-MS/MS method for quantitative detection of 22 kinds of pesticide in fruit and vegetable including organic phosphorus,carbamate & pyrethrin etc.Working was performed by Xcalibur software with ...To establish a new GC-MS/MS method for quantitative detection of 22 kinds of pesticide in fruit and vegetable including organic phosphorus,carbamate & pyrethrin etc.Working was performed by Xcalibur software with multitask mode.We Carried on qualitative and quantitative analysis to mass spectrum of MS/MS in order to obtained a credible experiment result.This method is sensitive and accurate,it is suitable for determination of multifarious pesticide residues.展开更多
采用气相色谱-氢火焰离子化检测器法(gas chromatography with hydrogen flame ionization detection,GCFID)、顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction coupled with gas chromatography-mass spectrometr...采用气相色谱-氢火焰离子化检测器法(gas chromatography with hydrogen flame ionization detection,GCFID)、顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry,HS-SPME-GC-MS)和电子鼻技术分析6种果酒中的挥发性成分,评价果酒风味轮廓特征的差异性。结果表明,GC-FID定量测定樱桃李酒,其中异戊醇、活性戊醇、β-苯乙醇含量最高,乙酸乙酯含量最低;木瓜酒中正丙醇、2,3-丁二醇、癸酸乙酯、乙酸含量最高; 3-羟基-2-丁酮含量在樱桃李酒中最高,山楂酒、甜橙酒中最少。HP-SPME-GC-MS鉴定果酒中挥发性物质94种,其中醇类23种,酯类43种,醛酮类10种,酸类8种,酚类2种,苯环类5种,烷烃类3种。山楂酒、菠萝酒、木瓜酒、甜橙酒、无花果酒和樱桃李酒中香气物质数量分别为34、44、45、45、33、47种。其中山楂酒、木瓜酒和无花果酒中未检出酚类、烷烃类物质。电子鼻对不同果酒香气的区分效果无重叠,W5S传感器区分果酒香气能力最强。比较而言,菠萝酒和樱桃李酒的口感更圆润,香气更愉悦,感官得分最高。展开更多
A method for determination of fatty acids(FA) compositions in human serum by gas chromatography time-of flight mass spectrometry(GC-TOF MS) method was established.The FA in serum were directly transformed into the fat...A method for determination of fatty acids(FA) compositions in human serum by gas chromatography time-of flight mass spectrometry(GC-TOF MS) method was established.The FA in serum were directly transformed into the fatty acid methyl esters by 2.5% H2SO4-methanol.Heptadecanoic acid methyl esters were used as internal standard.The detection and separation of all the FA were performed within 33 min.The established method has the characteristic of simple operation,rapid analysis,high accuracy,large amount of information and safety.So it is suitable for the scientific research to the disease correlating FA.展开更多
Poly brominated biphenyl(PBBs) and poly brominated diphenyl ether(PBDEs) in polymers of electrotechnical products have been extracted with toluene and analyzed by gas chromatography-mass spectrometry (GC-MS).The resul...Poly brominated biphenyl(PBBs) and poly brominated diphenyl ether(PBDEs) in polymers of electrotechnical products have been extracted with toluene and analyzed by gas chromatography-mass spectrometry (GC-MS).The result has more credibility when the nature of the sample was determined by retention time and the proportion of characteristic ions.PBBs and PBDEs were quantified by internal standard method and 2′,3,3′,4,4′,5,5′,6,6′-decachlorobiphenyl was used as internal standard.The GC-MS experimental results show,that the average spiked recoveries ranged from 81% to 110%,that the relative standard deviations(RSD) ranged from 1.54% to 8.65%.The research results also showed that the method presented simplicity-operating,excellent linearity and reproducibility.展开更多
Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by...Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by high resolution gas chromatography-high resolution mass spectrometry.Comparisons of the three methods were carried out by recovery of PCDD/Fs,solvent consumption and extraction time.The results showed that all of the method could extract labeled PCDD/Fs efficiently.ASE was a time saving procedure with lowest consumption of solvents compared with the other two methods.展开更多
建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证...建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证，同位素内标法定量。在1～40μg / L 范围内氟乐灵农药的线性关系良好；方法定量限（LOQ）为0.02μg / kg；对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验，平均回收率均处于80％～100％之间，RSD≤10.3％；无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。展开更多
Ionic liquids ( ILs) based ultrasonic-assisted extract has been applied for the extraction of essential oil from Persicaria minor leaves. The effects of temperature,sonication time,and particle size of the plant mater...Ionic liquids ( ILs) based ultrasonic-assisted extract has been applied for the extraction of essential oil from Persicaria minor leaves. The effects of temperature,sonication time,and particle size of the plant material on the yield of essential oil were investigated. Among the different ILs employed,1-ethyl-3-methyli midazolium acetate was the most effective,providing a 9. 55% yield of the essential oil under optimum conditions( 70 ℃,25 min,IL ∶hexane ratio of 7 ∶10 ( v /v) ,particle size 60-80 mesh) . The performance of 1-ethyl-3-methylimidazolium acetate in the extraction was attributed to its lowviscosity and ability to disintegrate the structural matrix of the plant material. The ability of 1-ethyl-3-methylimidazolium acetate was also confirmed using the conductor like-screening model for realistic solvents. This research proves that ILs can be used to extract essential oils from lignocellulosic biomass.展开更多
The non-edible oils are believed to be one of the major feedstock for the production of biodiesel in future.In the present study,we investigated the production of Jatropha oil methyl esters（JOMEs） via alkali-catalyz...The non-edible oils are believed to be one of the major feedstock for the production of biodiesel in future.In the present study,we investigated the production of Jatropha oil methyl esters（JOMEs） via alkali-catalyzed transesterification route.The biophysical characteristics of Jatropha oil were found within the optimal range in accordance with ASTM standards as a substitute diesel fuel.The chemical composition and production yield of as-synthesized biodiesel were confirmed by various analytical techniques such as FT-IR,1H NMR,13 C NMR and gas chromatography coupled with mass spectrometry.A high percentage conversion,～96.09%,of fatty acids into esters was achieved under optimized transesterification conditions with 6 ：1 oil to methanol ratio and 0.9 wt% Na OH for 50 min at ～60°C.Moreover,twelve fatty acids methyl esters（FAME） were quantified in the GC/MS analysis and it was interesting to note that the mass fragmentation pattern of saturated,monounsaturated and diunsaturated FAME was comparable with the literature reported values.展开更多
The determination of emitted Biogenic Volatile Compounds （BioVOCs） profile via Field Air Analysis （FAA） - Solid Phase Micro Extraction （75μm Carboxen/PDMS portable field sampler） was performed using GC-MS. The ...The determination of emitted Biogenic Volatile Compounds （BioVOCs） profile via Field Air Analysis （FAA） - Solid Phase Micro Extraction （75μm Carboxen/PDMS portable field sampler） was performed using GC-MS. The six sampling sites located in the Natural Park of Ampezzo Dolomites, part of the UNESCO＇s World Heritage List, are characterized by different predominating vegetation. The ubiquitous compound hexanal was chosen as internal standard, in order to compare the amounts of the different compound in the different sites. The main terpenes identified were α-pinene, 13-pinene, 6-3-carene and d-limonene, while 1,8 cineole was the highest abundant oxygenated terpene. In the site next the＇national road a higher amount of benzene derivatives （ben- zene, toluene, o-xylene, p-xylene and ethylbenzene） were observed. In the site relatively close to the road a marked decrease of benzene deriva- tives was observed. In the sites close to conifers （i.e. Fir, Pine and Larch） the terpenic content observed was higher than in the site close to the mixed forest （mainly large-leaf and some conifers）. Some terpenes were observed also in the high-quote meadow site, although of lower abun- dance than in the other sites. The highest abundance of terpenes was ob- served in the Pinus cerebra （Swiss Pine） site.展开更多
We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation,identified the obtained compounds using gas chromatography–mass spectrometry(GC–MS) and Fourier transform...We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation,identified the obtained compounds using gas chromatography–mass spectrometry(GC–MS) and Fourier transform-infrared spectroscopy(FT-IR),and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic voltammetry.On the basis of GC–MS spectra,38 compounds were identified in the essential oil from leaves and 26 in the oil from bark.The bark oil contained 13.44% b-Farnesene(sesquiterpene),10.45% caryophyllene oxide(sesquiterpene) and 6.6% spathulenol,(2 Z,6 E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol(sesquiterpene alcohol),9.0% caryophyllene oxide(sesquiterpenoids) and 6.3% decyl acetate(ester).FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones,carboxylic acid,alcohols,esters and ethers in both oil types.UV–visible absorption spectra showed maximum absorbance at 245,290 and 402 nm for bark oil,and 250,285 and 325 nm for leaf.Bark oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 nm.The essential oil had significant anti-inflammatory activity,and the reduction potential of the leaf oil was-0.44 and-0.56 e V for bark.展开更多
The detector,as well as being an essential supporting device for the gas chromatography(GC) has also played a critical role in the development of the technique as a whole.The mass spectrometer(MS) is still the commonl...The detector,as well as being an essential supporting device for the gas chromatography(GC) has also played a critical role in the development of the technique as a whole.The mass spectrometer(MS) is still the commonly praised detector as before.In fact,the information of fragmentation patterns is seldom used in practice,and the GC-MS instrument is even more expensive.For today's analytical problems,it seems that element specific detectors can and should be used for many applications rather than GC-MS.展开更多
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
文摘To establish a new GC-MS/MS method for quantitative detection of 22 kinds of pesticide in fruit and vegetable including organic phosphorus,carbamate & pyrethrin etc.Working was performed by Xcalibur software with multitask mode.We Carried on qualitative and quantitative analysis to mass spectrum of MS/MS in order to obtained a credible experiment result.This method is sensitive and accurate,it is suitable for determination of multifarious pesticide residues.
文摘采用气相色谱-氢火焰离子化检测器法(gas chromatography with hydrogen flame ionization detection,GCFID)、顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry,HS-SPME-GC-MS)和电子鼻技术分析6种果酒中的挥发性成分,评价果酒风味轮廓特征的差异性。结果表明,GC-FID定量测定樱桃李酒,其中异戊醇、活性戊醇、β-苯乙醇含量最高,乙酸乙酯含量最低;木瓜酒中正丙醇、2,3-丁二醇、癸酸乙酯、乙酸含量最高; 3-羟基-2-丁酮含量在樱桃李酒中最高,山楂酒、甜橙酒中最少。HP-SPME-GC-MS鉴定果酒中挥发性物质94种,其中醇类23种,酯类43种,醛酮类10种,酸类8种,酚类2种,苯环类5种,烷烃类3种。山楂酒、菠萝酒、木瓜酒、甜橙酒、无花果酒和樱桃李酒中香气物质数量分别为34、44、45、45、33、47种。其中山楂酒、木瓜酒和无花果酒中未检出酚类、烷烃类物质。电子鼻对不同果酒香气的区分效果无重叠,W5S传感器区分果酒香气能力最强。比较而言,菠萝酒和樱桃李酒的口感更圆润,香气更愉悦,感官得分最高。
文摘A method for determination of fatty acids(FA) compositions in human serum by gas chromatography time-of flight mass spectrometry(GC-TOF MS) method was established.The FA in serum were directly transformed into the fatty acid methyl esters by 2.5% H2SO4-methanol.Heptadecanoic acid methyl esters were used as internal standard.The detection and separation of all the FA were performed within 33 min.The established method has the characteristic of simple operation,rapid analysis,high accuracy,large amount of information and safety.So it is suitable for the scientific research to the disease correlating FA.
文摘Poly brominated biphenyl(PBBs) and poly brominated diphenyl ether(PBDEs) in polymers of electrotechnical products have been extracted with toluene and analyzed by gas chromatography-mass spectrometry (GC-MS).The result has more credibility when the nature of the sample was determined by retention time and the proportion of characteristic ions.PBBs and PBDEs were quantified by internal standard method and 2′,3,3′,4,4′,5,5′,6,6′-decachlorobiphenyl was used as internal standard.The GC-MS experimental results show,that the average spiked recoveries ranged from 81% to 110%,that the relative standard deviations(RSD) ranged from 1.54% to 8.65%.The research results also showed that the method presented simplicity-operating,excellent linearity and reproducibility.
文摘Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by high resolution gas chromatography-high resolution mass spectrometry.Comparisons of the three methods were carried out by recovery of PCDD/Fs,solvent consumption and extraction time.The results showed that all of the method could extract labeled PCDD/Fs efficiently.ASE was a time saving procedure with lowest consumption of solvents compared with the other two methods.
文摘建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证，同位素内标法定量。在1～40μg / L 范围内氟乐灵农药的线性关系良好；方法定量限（LOQ）为0.02μg / kg；对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验，平均回收率均处于80％～100％之间，RSD≤10.3％；无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。
文摘Ionic liquids ( ILs) based ultrasonic-assisted extract has been applied for the extraction of essential oil from Persicaria minor leaves. The effects of temperature,sonication time,and particle size of the plant material on the yield of essential oil were investigated. Among the different ILs employed,1-ethyl-3-methyli midazolium acetate was the most effective,providing a 9. 55% yield of the essential oil under optimum conditions( 70 ℃,25 min,IL ∶hexane ratio of 7 ∶10 ( v /v) ,particle size 60-80 mesh) . The performance of 1-ethyl-3-methylimidazolium acetate in the extraction was attributed to its lowviscosity and ability to disintegrate the structural matrix of the plant material. The ability of 1-ethyl-3-methylimidazolium acetate was also confirmed using the conductor like-screening model for realistic solvents. This research proves that ILs can be used to extract essential oils from lignocellulosic biomass.
基金financial and moral support from the National Centre for Physics Islamabad,Pakistan to carry out of this present research workDeanship of Scientific Research at King Saud University for it’s funding of this research through the Research Group Project no RGP-VPP-345
文摘The non-edible oils are believed to be one of the major feedstock for the production of biodiesel in future.In the present study,we investigated the production of Jatropha oil methyl esters（JOMEs） via alkali-catalyzed transesterification route.The biophysical characteristics of Jatropha oil were found within the optimal range in accordance with ASTM standards as a substitute diesel fuel.The chemical composition and production yield of as-synthesized biodiesel were confirmed by various analytical techniques such as FT-IR,1H NMR,13 C NMR and gas chromatography coupled with mass spectrometry.A high percentage conversion,～96.09%,of fatty acids into esters was achieved under optimized transesterification conditions with 6 ：1 oil to methanol ratio and 0.9 wt% Na OH for 50 min at ～60°C.Moreover,twelve fatty acids methyl esters（FAME） were quantified in the GC/MS analysis and it was interesting to note that the mass fragmentation pattern of saturated,monounsaturated and diunsaturated FAME was comparable with the literature reported values.
文摘The determination of emitted Biogenic Volatile Compounds （BioVOCs） profile via Field Air Analysis （FAA） - Solid Phase Micro Extraction （75μm Carboxen/PDMS portable field sampler） was performed using GC-MS. The six sampling sites located in the Natural Park of Ampezzo Dolomites, part of the UNESCO＇s World Heritage List, are characterized by different predominating vegetation. The ubiquitous compound hexanal was chosen as internal standard, in order to compare the amounts of the different compound in the different sites. The main terpenes identified were α-pinene, 13-pinene, 6-3-carene and d-limonene, while 1,8 cineole was the highest abundant oxygenated terpene. In the site next the＇national road a higher amount of benzene derivatives （ben- zene, toluene, o-xylene, p-xylene and ethylbenzene） were observed. In the site relatively close to the road a marked decrease of benzene deriva- tives was observed. In the sites close to conifers （i.e. Fir, Pine and Larch） the terpenic content observed was higher than in the site close to the mixed forest （mainly large-leaf and some conifers）. Some terpenes were observed also in the high-quote meadow site, although of lower abun- dance than in the other sites. The highest abundance of terpenes was ob- served in the Pinus cerebra （Swiss Pine） site.
文摘We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation,identified the obtained compounds using gas chromatography–mass spectrometry(GC–MS) and Fourier transform-infrared spectroscopy(FT-IR),and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic voltammetry.On the basis of GC–MS spectra,38 compounds were identified in the essential oil from leaves and 26 in the oil from bark.The bark oil contained 13.44% b-Farnesene(sesquiterpene),10.45% caryophyllene oxide(sesquiterpene) and 6.6% spathulenol,(2 Z,6 E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol(sesquiterpene alcohol),9.0% caryophyllene oxide(sesquiterpenoids) and 6.3% decyl acetate(ester).FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones,carboxylic acid,alcohols,esters and ethers in both oil types.UV–visible absorption spectra showed maximum absorbance at 245,290 and 402 nm for bark oil,and 250,285 and 325 nm for leaf.Bark oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 nm.The essential oil had significant anti-inflammatory activity,and the reduction potential of the leaf oil was-0.44 and-0.56 e V for bark.
文摘The detector,as well as being an essential supporting device for the gas chromatography(GC) has also played a critical role in the development of the technique as a whole.The mass spectrometer(MS) is still the commonly praised detector as before.In fact,the information of fragmentation patterns is seldom used in practice,and the GC-MS instrument is even more expensive.For today's analytical problems,it seems that element specific detectors can and should be used for many applications rather than GC-MS.
