The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compounds in straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with ...The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compounds in straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with a sulfur chemiluminescence detector to harvest a satisfactory result. The identification of the structure of sulfur compounds by comprehensive two-dimensional gas chromatography coupled with the time-of-flight mass spectrometry indicated that cyclo-sulfides, benzothiophenes, dibenzothiophenes, dihydro-benzothiophenes and tetrahydro-dibenzothiophenes were included in straightrun diesel obtained from the Arab medium crude(AM). A total of 259 individual compounds were detected and their molecular structures were identified. The analytical method was approved as an effective way to characterize the composition of sulfur compounds, which reduced the interference of other compounds, facilitated the data presentation and provided more detailed information about molecular composition of sulfur compounds.展开更多
Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of produc...Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of production and everyday consumption. Therefore there is a need to apply new and sufficiently sensitive analytical methods, which can detect the presence of these contaminants even in very low concentrations. This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues, mainly from the group of non-steroidal anti-inflammatory drugs （salicylic acid, acetylsalicylic acid, ctofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen, and dicofenac）, in wastewaters and surface waters. This analytical method is based on solid phase extraction, derivatization by N-methyl-N-（trimethylsilyl）trifluoroacetamide （MSTFA） and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection （GC×GC- TOF MS）. Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix. The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice, Czech Republic. The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of μg/L in wastewater.展开更多
Two-dimensional electrophoresis（2-DE） of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kD...Two-dimensional electrophoresis（2-DE） of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kDa-31 kDa and 43 kDa-66 kDa, and more proteins were detected between 14kDa and 31 kDa. With the improved protein preparation, the two-dimensional electrophoresis patterns indicated that the relative molecular weights of the proteins were between 14kDa and 100kDa, and most of them ranged from 14 kDa to 31 kDa. This was consistent with the result of the SDS-PAGE analysis. The isoelectric points were found to lie between 3.0 and 8.0, and most of them were in the range of 3.0-6.0. Better separation effect was acquired with pre-prepared immobilized gradient （IPG） strip （pH 3-5.6）, and about 320 protein spots could be visualized on the 2-DE map by staining. Within pH 3-l0 and pH 3-5.6 strips, the protein samples of Alexandrium sp. LC3 could be separated well.展开更多
Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS) is commercially available in the 1990s,with the characteristics of large peak capacity,high resolution,h...Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS) is commercially available in the 1990s,with the characteristics of large peak capacity,high resolution,high sensitivity,etc.However,its application to the petroleum and geological analyses is just emerging in China and overseas.In this research,the analytical method for petroleum aromatic fraction using GC×GC-TOFMS is set up,via the choice of the column system and optimization of setting parameters,such as temperature programming,modulation time,hot pulse time,flow rate of carrier gas,data acquisition rate and data processing.The results indicate that different polar compounds of aromatic fraction distribute as bands on structured GC×GC chromatogram.Within each band,homologous compounds appear as a roof-tile structure based on the number of substituent residues.The aromatic compounds are identified and characterized according to the GC×GC chromatogram and mass spectra.According to the polarity and the number of rings,aromatic compounds are spatially present on one chromatogram,which directly reflects the distribution characteristics of complex compounds of aromatic hydrocarbons.In addition,quantitative analysis is favored as some overlapped peaks on traditional GC-MS chromatogram have been separated completely on GC×GC.Some heterocyclic atom aromatic compounds at trace level can be clearly identified using this method,for polarity differences from other interfered aromatic compounds.The development of this method and chromatogram recognition offer petroleum geologists a practical example for the application performance of GC×GC-TOFMS.展开更多
The saturated and aromatic hydrocarbon fractions of crude oil samples have been analyzed by using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry （GCxGC-TOFMS） and conventional...The saturated and aromatic hydrocarbon fractions of crude oil samples have been analyzed by using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry （GCxGC-TOFMS） and conventional gas chro- matography-mass spectrometry （GC-MS）. In order to investigate the consistency and discrepancy of the obtained data from the two instruments, some petroleum geochemical parameters have been compared. A comparison of 23 geochemical parameters indicates that 10 parameters are comparable from the two instruments with less than 5% deviations. Therefore, GCxGC-TOFMS is equivalent to conventional GC-MS in some geochemical parameter acquisitions. However, the other 13 parameters are discrepant, including gammacerane / αβ-hopane, Ts/Tm, 2-ethyl-naphthalene / 1-ethyl-naphthalene （ENR）, （2, 6-dimethyl-naphthalene ＋2,7-dimethyl-naphthalene） / 1,5-dimethyl-naphthalene （DNR）, etc. Furthermore, compared to GCxGC-TOFMS, some low concentration compounds could not be detected by the conventional GC-MS, which results in the missing of related geochemical data. Normally, this is caused by the limited separation power and peak capacity of the conventional GC column. Besides, the co-eluting peak integrations are also affected significantly due to the incomplete separation of the compounds. Some low concentration compounds might not be detected because of the interference from the baseline noise or from other substances. GCxGC-TOFMS prevails in compound separation against the conventional GC-MS by avoiding co-elution, which achieves more accurate and precise peak area measurement with the presence of a true baseline. So petroleum geochemical parameters obtained from the GCxGC-TOFMS GCxGC-TOFMS may become one of the most effective analytical are more reliable than those from the conventional GC-MS tools for the oil and gas geochemical study.展开更多
Objectives:The ageing process has a significant impact on the aroma of Chinese Baijiu,which could strengthen the desirable flavor characteristics and reduce the undesirable ones.The aim of this study was to observe th...Objectives:The ageing process has a significant impact on the aroma of Chinese Baijiu,which could strengthen the desirable flavor characteristics and reduce the undesirable ones.The aim of this study was to observe the in itiation of mean in gful cha nges in volatile fracti on and locate the ageing markers during ageing storage of Chinese Highland Qingke Baijiu.Materials and Methods:Samples of Chinese Qingke Baijiu were aged for 0,1,2,3,4,5,6,7,8,9,10,and 11 mon ths before an alysis.The samples were isolated by liquid-liquid extraction and then analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry.The acquired data were processed by untargeted and targeted metabolomics approach to locate the ageing markers.Results:The untargeted metabolomics analysis(hierarchical clustering analysis,HCA)shows that the chemical composition of Qingke Baijiu presents a statistically sigrdficant deviation from the reference scenario after 5 mon ths.Subsequently,supervised statistics analysis(orthogo nal partial least squares discrimination analysis)was performed to locate the markers,which changed sigrdficantly during ageing.Fifteen markers were located,and seven of them were acetals.Notably,1,1-diethoxy-propane,1,1-diethoxy-butane,and 1,1-diethoxy-3-methyl-butane are important contributors to the flavor of Chinese Baijiu.The identified markers were applied for the untargeted metabolomics(HCA),and the results revealed that these markers could divide the Qingke Baijiu into two ageing stages,0-5 months and 6-11 months.Conclusion:The results suggest that it is a valuable tool for monitoring the changes of volatile compounds and locating the age markers in Chinese Baijiu.展开更多
To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis. A comprehensive two-dimensional gas chromatography (GCxGC) and high-resolution time-of-flight mass spectro...To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis. A comprehensive two-dimensional gas chromatography (GCxGC) and high-resolution time-of-flight mass spectrometry (HR-TOF/MS) with colorized fuzzy difference (CFD) method was used to investigate the effect of sulfur-fumigation on the volatile components from Radix Angelicae Sinensis. Twenty-five compounds that were found in sun-dried samples disappeared in sulfur-fumigated samples. Seventeen volatile components including two sulfur-containing compounds were newly generated for the first time in volatile oils of sulfur-fumigated Radix Angelicae Sinensis. The strategy can be successfully applied to rapidly and holistically discriminate sun-dried and sulfur-fumigated Radix Angelicae Sinensis. GCxGC-HR-TOF/MS based CFD is a powerful and feasible approach for the global quality evaluation of Radix Angelicae Sinensis as well as other herbal medicines.展开更多
Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constitu...Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constituents of two types of tripterygium glycosides tablets(TGT).The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared.C8andC18 column were used for the separation of the first展开更多
采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry...采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry,GC×GC-TOF-MS)以及香气活度值(odour active value,OAV),对红星二锅头白酒的挥发性成分进行全面解析。研究发现,HS-SPME、LLE分别定性出928、802种挥发性化合物,共计定性出1304种挥发性化合物,共同定性出426种挥发性化合物。基于HS-SPME数据,通过香气数据库筛选出具有香气特征的382种香气化合物,其中酯类相对百分含量占比最高,其次是醇类、酸类和醛类。计算得到了49种香气化合物OAV>1,其中酯类(辛酸乙酯、异戊酸乙酯等)和萜烯类(β-大马酮)对白酒风味的贡献最大,醛类(异戊醛、己醛等)和含硫类(二甲基三硫)其次,醇类(1-辛烯-3-醇)和含氮类(2,3,5-三甲基吡嗪)也有一定风味贡献。该研究丰富了红星二锅头白酒的风味研究,也为下一步生产研究及调控提供了理论和数据支撑。展开更多
One-dimensional liquid chromatography(1D-LC)is routinely applied to the analysis of all kinds of samples in different fields.With the introduction of UHPLC instruments and sub-2micron particle columns,the separation e...One-dimensional liquid chromatography(1D-LC)is routinely applied to the analysis of all kinds of samples in different fields.With the introduction of UHPLC instruments and sub-2micron particle columns,the separation efficiency was greatly improved.To resolve all components of complex samples,however,1D-LC does not provide enough resolving power,or peak capacity.In addition,to separate compounds co-eluting in 1D-LC,increasing the separation efficiency by increasing展开更多
In this study, a system involving two-dimensional, column-switching high-performance liquid chromatography （HPLC） coupled with tandem mass spectrometry （LC-MS/MS） was developed and optimized for the analysis of an...In this study, a system involving two-dimensional, column-switching high-performance liquid chromatography （HPLC） coupled with tandem mass spectrometry （LC-MS/MS） was developed and optimized for the analysis of antibiotics and their related substances. In the first-dimensional chromatography, the analytes were separated on a zwitterion exchange-reversed phase-hydrophitic interaction （ZIC-RP-HILIC） mixed-mode column coupled with tandem mass spectrometry （LC-MS/MS）. A commonly used reversed phase LC column was employed in the second-dimensional chromatography. The mobile phase for the ZIC-RP-HILIC mixed-mode chromatography consisted of a volatile buffer that was compatible with LC-MS/MS, which enhanced the efficiency of ionization for structure elucidation. The antibiotic impurities eluted in the ion-pairing reversed phase chromatography were directly characterized by the ZIC-RP-HILIC-MS system, and the orthogonal separation of ZIC-RP-HILIC mixed-mode chromatography and reversed phase LC provided extra confidence that no impurity was missed. The efficiency of this method was demonstrated in the analysis of penicillin V potassium, oxacillin sodium, ceftriaxone sodium, and their impurities. In addition, this method is convenient for impurity profiling of antibiotics, and may be used for the analysis of other pharmaceutical ingredients.展开更多
A polarization-independent nonmechanical laser beam steering scheme is proposed to realize continuous two-dimensional（2 D） scanning with high efficiency, where the core components are two polarization-dependent devi...A polarization-independent nonmechanical laser beam steering scheme is proposed to realize continuous two-dimensional（2 D） scanning with high efficiency, where the core components are two polarization-dependent devices, which are called liquid crystal optical phased arrays（LC-OPAs）. These two one-dimensional（1D） devices are orthogonally cascaded to work on the state of azimuthal and elevation steering, respectively. Properties of polarization independence as well as 2D beam steering are mathematically and experimentally verified with a good agreement. Based on the experimental setup, linearly polarized beams with different polarization angles are steered with high accuracy. The measured angular deviations are less than 5 μrad, which is on the same order of the accuracy of the measurement system. This polarization-independent 2 D laser beam steering scheme has potential application for nonmechanical laser communication, lidar, and other LC-based systems.展开更多
Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） ...Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.展开更多
Genetic algorithm and partial least square（GA-PLS）,kernel PLS（KPLS） and Levenberg-Marquardt artificial neural network（L-M ANN） techniques were used to investigate the correlation between retention time（RT） and...Genetic algorithm and partial least square（GA-PLS）,kernel PLS（KPLS） and Levenberg-Marquardt artificial neural network（L-M ANN） techniques were used to investigate the correlation between retention time（RT） and descriptors for 15 nanoparticle compounds obtained by the comprehensive two-dimensional gas chromatography system（GC × GC）.Application of the dodecanethiol monolayer-protected gold nanoparticle（MPN） column was for a high-speed separation as the second column of GC × GC.The L-M ANN model with the final optimum network architecture of [13-5-1] gave a significantly better performance than the other models.This is the first research on the quantitative structure-retention relationship（QSRR） of nanoparticle compounds using the GA-PLS,GA-KPLS and L-M ANN.展开更多
基金financially supported by the National Basic Research Program of China (973 Program) (2012CB224800)
文摘The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compounds in straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with a sulfur chemiluminescence detector to harvest a satisfactory result. The identification of the structure of sulfur compounds by comprehensive two-dimensional gas chromatography coupled with the time-of-flight mass spectrometry indicated that cyclo-sulfides, benzothiophenes, dibenzothiophenes, dihydro-benzothiophenes and tetrahydro-dibenzothiophenes were included in straightrun diesel obtained from the Arab medium crude(AM). A total of 259 individual compounds were detected and their molecular structures were identified. The analytical method was approved as an effective way to characterize the composition of sulfur compounds, which reduced the interference of other compounds, facilitated the data presentation and provided more detailed information about molecular composition of sulfur compounds.
基金supported by the Institute Research Plan(No. FCH-S-12-4) from the Ministry of Education,Youth and Sports of the Czech Republic
文摘Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of production and everyday consumption. Therefore there is a need to apply new and sufficiently sensitive analytical methods, which can detect the presence of these contaminants even in very low concentrations. This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues, mainly from the group of non-steroidal anti-inflammatory drugs （salicylic acid, acetylsalicylic acid, ctofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen, and dicofenac）, in wastewaters and surface waters. This analytical method is based on solid phase extraction, derivatization by N-methyl-N-（trimethylsilyl）trifluoroacetamide （MSTFA） and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection （GC×GC- TOF MS）. Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix. The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice, Czech Republic. The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of μg/L in wastewater.
基金This research was financially supported by National Natural Science Foundation of China （40206022）.
文摘Two-dimensional electrophoresis（2-DE） of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kDa-31 kDa and 43 kDa-66 kDa, and more proteins were detected between 14kDa and 31 kDa. With the improved protein preparation, the two-dimensional electrophoresis patterns indicated that the relative molecular weights of the proteins were between 14kDa and 100kDa, and most of them ranged from 14 kDa to 31 kDa. This was consistent with the result of the SDS-PAGE analysis. The isoelectric points were found to lie between 3.0 and 8.0, and most of them were in the range of 3.0-6.0. Better separation effect was acquired with pre-prepared immobilized gradient （IPG） strip （pH 3-5.6）, and about 320 protein spots could be visualized on the 2-DE map by staining. Within pH 3-l0 and pH 3-5.6 strips, the protein samples of Alexandrium sp. LC3 could be separated well.
基金sponsored by the Science and Technology Management Department of China National Petroleum Corporation
文摘Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS) is commercially available in the 1990s,with the characteristics of large peak capacity,high resolution,high sensitivity,etc.However,its application to the petroleum and geological analyses is just emerging in China and overseas.In this research,the analytical method for petroleum aromatic fraction using GC×GC-TOFMS is set up,via the choice of the column system and optimization of setting parameters,such as temperature programming,modulation time,hot pulse time,flow rate of carrier gas,data acquisition rate and data processing.The results indicate that different polar compounds of aromatic fraction distribute as bands on structured GC×GC chromatogram.Within each band,homologous compounds appear as a roof-tile structure based on the number of substituent residues.The aromatic compounds are identified and characterized according to the GC×GC chromatogram and mass spectra.According to the polarity and the number of rings,aromatic compounds are spatially present on one chromatogram,which directly reflects the distribution characteristics of complex compounds of aromatic hydrocarbons.In addition,quantitative analysis is favored as some overlapped peaks on traditional GC-MS chromatogram have been separated completely on GC×GC.Some heterocyclic atom aromatic compounds at trace level can be clearly identified using this method,for polarity differences from other interfered aromatic compounds.The development of this method and chromatogram recognition offer petroleum geologists a practical example for the application performance of GC×GC-TOFMS.
基金supported by the Science and Technology Management Department of China National Petroleum Corporation (Grant No. 2008A-0603)
文摘The saturated and aromatic hydrocarbon fractions of crude oil samples have been analyzed by using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry （GCxGC-TOFMS） and conventional gas chro- matography-mass spectrometry （GC-MS）. In order to investigate the consistency and discrepancy of the obtained data from the two instruments, some petroleum geochemical parameters have been compared. A comparison of 23 geochemical parameters indicates that 10 parameters are comparable from the two instruments with less than 5% deviations. Therefore, GCxGC-TOFMS is equivalent to conventional GC-MS in some geochemical parameter acquisitions. However, the other 13 parameters are discrepant, including gammacerane / αβ-hopane, Ts/Tm, 2-ethyl-naphthalene / 1-ethyl-naphthalene （ENR）, （2, 6-dimethyl-naphthalene ＋2,7-dimethyl-naphthalene） / 1,5-dimethyl-naphthalene （DNR）, etc. Furthermore, compared to GCxGC-TOFMS, some low concentration compounds could not be detected by the conventional GC-MS, which results in the missing of related geochemical data. Normally, this is caused by the limited separation power and peak capacity of the conventional GC column. Besides, the co-eluting peak integrations are also affected significantly due to the incomplete separation of the compounds. Some low concentration compounds might not be detected because of the interference from the baseline noise or from other substances. GCxGC-TOFMS prevails in compound separation against the conventional GC-MS by avoiding co-elution, which achieves more accurate and precise peak area measurement with the presence of a true baseline. So petroleum geochemical parameters obtained from the GCxGC-TOFMS GCxGC-TOFMS may become one of the most effective analytical are more reliable than those from the conventional GC-MS tools for the oil and gas geochemical study.
基金supported by the National Key Research and Development Program of China(2016YFD0400500)the National Natural Science Foundation of China(No.32001826).
文摘Objectives:The ageing process has a significant impact on the aroma of Chinese Baijiu,which could strengthen the desirable flavor characteristics and reduce the undesirable ones.The aim of this study was to observe the in itiation of mean in gful cha nges in volatile fracti on and locate the ageing markers during ageing storage of Chinese Highland Qingke Baijiu.Materials and Methods:Samples of Chinese Qingke Baijiu were aged for 0,1,2,3,4,5,6,7,8,9,10,and 11 mon ths before an alysis.The samples were isolated by liquid-liquid extraction and then analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry.The acquired data were processed by untargeted and targeted metabolomics approach to locate the ageing markers.Results:The untargeted metabolomics analysis(hierarchical clustering analysis,HCA)shows that the chemical composition of Qingke Baijiu presents a statistically sigrdficant deviation from the reference scenario after 5 mon ths.Subsequently,supervised statistics analysis(orthogo nal partial least squares discrimination analysis)was performed to locate the markers,which changed sigrdficantly during ageing.Fifteen markers were located,and seven of them were acetals.Notably,1,1-diethoxy-propane,1,1-diethoxy-butane,and 1,1-diethoxy-3-methyl-butane are important contributors to the flavor of Chinese Baijiu.The identified markers were applied for the untargeted metabolomics(HCA),and the results revealed that these markers could divide the Qingke Baijiu into two ageing stages,0-5 months and 6-11 months.Conclusion:The results suggest that it is a valuable tool for monitoring the changes of volatile compounds and locating the age markers in Chinese Baijiu.
基金Supported by the National Natural Science Foundation of China(No.81173546 and No.30940093)the Natural Science Foundation of Jiangsu Province,China(No.BK2009495)+4 种基金the International Science and Technology Cooperation Project of Jiangsu Province,China(No.BZ2011053)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,No.2011ZYX2-001)the Postgraduate Research Innovation Project of Jiangsu Higher Education Institutions(No.KYLX_0975)the Chinese Medicine Research Program of Zhejiang Province,China(No.2014ZQ008)the Science Foundation of Zhejiang Chinese Medical University(No.2013ZZ12)
文摘To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis. A comprehensive two-dimensional gas chromatography (GCxGC) and high-resolution time-of-flight mass spectrometry (HR-TOF/MS) with colorized fuzzy difference (CFD) method was used to investigate the effect of sulfur-fumigation on the volatile components from Radix Angelicae Sinensis. Twenty-five compounds that were found in sun-dried samples disappeared in sulfur-fumigated samples. Seventeen volatile components including two sulfur-containing compounds were newly generated for the first time in volatile oils of sulfur-fumigated Radix Angelicae Sinensis. The strategy can be successfully applied to rapidly and holistically discriminate sun-dried and sulfur-fumigated Radix Angelicae Sinensis. GCxGC-HR-TOF/MS based CFD is a powerful and feasible approach for the global quality evaluation of Radix Angelicae Sinensis as well as other herbal medicines.
文摘Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constituents of two types of tripterygium glycosides tablets(TGT).The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared.C8andC18 column were used for the separation of the first
文摘采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry,GC×GC-TOF-MS)以及香气活度值(odour active value,OAV),对红星二锅头白酒的挥发性成分进行全面解析。研究发现,HS-SPME、LLE分别定性出928、802种挥发性化合物,共计定性出1304种挥发性化合物,共同定性出426种挥发性化合物。基于HS-SPME数据,通过香气数据库筛选出具有香气特征的382种香气化合物,其中酯类相对百分含量占比最高,其次是醇类、酸类和醛类。计算得到了49种香气化合物OAV>1,其中酯类(辛酸乙酯、异戊酸乙酯等)和萜烯类(β-大马酮)对白酒风味的贡献最大,醛类(异戊醛、己醛等)和含硫类(二甲基三硫)其次,醇类(1-辛烯-3-醇)和含氮类(2,3,5-三甲基吡嗪)也有一定风味贡献。该研究丰富了红星二锅头白酒的风味研究,也为下一步生产研究及调控提供了理论和数据支撑。
文摘One-dimensional liquid chromatography(1D-LC)is routinely applied to the analysis of all kinds of samples in different fields.With the introduction of UHPLC instruments and sub-2micron particle columns,the separation efficiency was greatly improved.To resolve all components of complex samples,however,1D-LC does not provide enough resolving power,or peak capacity.In addition,to separate compounds co-eluting in 1D-LC,increasing the separation efficiency by increasing
基金The Key Projects in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(Grant No.2012BAK25B02)
文摘In this study, a system involving two-dimensional, column-switching high-performance liquid chromatography （HPLC） coupled with tandem mass spectrometry （LC-MS/MS） was developed and optimized for the analysis of antibiotics and their related substances. In the first-dimensional chromatography, the analytes were separated on a zwitterion exchange-reversed phase-hydrophitic interaction （ZIC-RP-HILIC） mixed-mode column coupled with tandem mass spectrometry （LC-MS/MS）. A commonly used reversed phase LC column was employed in the second-dimensional chromatography. The mobile phase for the ZIC-RP-HILIC mixed-mode chromatography consisted of a volatile buffer that was compatible with LC-MS/MS, which enhanced the efficiency of ionization for structure elucidation. The antibiotic impurities eluted in the ion-pairing reversed phase chromatography were directly characterized by the ZIC-RP-HILIC-MS system, and the orthogonal separation of ZIC-RP-HILIC mixed-mode chromatography and reversed phase LC provided extra confidence that no impurity was missed. The efficiency of this method was demonstrated in the analysis of penicillin V potassium, oxacillin sodium, ceftriaxone sodium, and their impurities. In addition, this method is convenient for impurity profiling of antibiotics, and may be used for the analysis of other pharmaceutical ingredients.
基金supported by the National Science Foundation of China(NSFC)(Nos.61405029,91438108,and61231012)the Shanghai Aerospace Science and Technology(SAST)(No.2015087)
文摘A polarization-independent nonmechanical laser beam steering scheme is proposed to realize continuous two-dimensional（2 D） scanning with high efficiency, where the core components are two polarization-dependent devices, which are called liquid crystal optical phased arrays（LC-OPAs）. These two one-dimensional（1D） devices are orthogonally cascaded to work on the state of azimuthal and elevation steering, respectively. Properties of polarization independence as well as 2D beam steering are mathematically and experimentally verified with a good agreement. Based on the experimental setup, linearly polarized beams with different polarization angles are steered with high accuracy. The measured angular deviations are less than 5 μrad, which is on the same order of the accuracy of the measurement system. This polarization-independent 2 D laser beam steering scheme has potential application for nonmechanical laser communication, lidar, and other LC-based systems.
基金funded by the National Natural Science Foundation of China(Grant No.41172126)the State Key Laboratory of Petroleum Resources and Prospecting(PRP/indep-2-1402)
文摘Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.
文摘Genetic algorithm and partial least square（GA-PLS）,kernel PLS（KPLS） and Levenberg-Marquardt artificial neural network（L-M ANN） techniques were used to investigate the correlation between retention time（RT） and descriptors for 15 nanoparticle compounds obtained by the comprehensive two-dimensional gas chromatography system（GC × GC）.Application of the dodecanethiol monolayer-protected gold nanoparticle（MPN） column was for a high-speed separation as the second column of GC × GC.The L-M ANN model with the final optimum network architecture of [13-5-1] gave a significantly better performance than the other models.This is the first research on the quantitative structure-retention relationship（QSRR） of nanoparticle compounds using the GA-PLS,GA-KPLS and L-M ANN.
