The present study describes guanidinium-based ionic liquids(GBILs) as stationary phases for capillary gas chromatography (CGC) and to the best of our knowledge,no related reports are available up to now.In this st...The present study describes guanidinium-based ionic liquids(GBILs) as stationary phases for capillary gas chromatography (CGC) and to the best of our knowledge,no related reports are available up to now.In this study,a hexaalkylguanidinium ionic liquid(DOTMG-NTf;) was synthesized and coated statically onto capillary columns.Selectivity of the stationary phase was evaluated by separating Grob test mixture,test mixture,alcohols mixture,and fatty acid methyl esters mixture,and thermal stability was investigated as well.The present study demonstrates that GBILs as CGC stationary phases exhibit satisfactory selectivity and thermal stability and have a great potential as new candidates for CGC stationary phases.展开更多
Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for t...Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35℃ and 1.0 mL/min, respectively. Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.展开更多
One chloride-terminated ionic liquid(CTIL) and two hydroxyl-terminated ionic liquids(HTILs) were synthesized and used as stationary phases for capillary gas chromatography(CGC).Molecular interactions of these st...One chloride-terminated ionic liquid(CTIL) and two hydroxyl-terminated ionic liquids(HTILs) were synthesized and used as stationary phases for capillary gas chromatography(CGC).Molecular interactions of these stationary phases were evaluated by Abraham solvation parameter model,indicating that the CTIL exhibits remarkably strong H-bond basicity and the HTILs possess both H-bond basicity and acidity.The molecular interactions were further confirmed by separation of a complex mixture consisting of ketones,aldehydes,esters,alcohols and aromatic compounds.It was found that the obtained solvation parameters correlate well with the chromatographic performances of the analytes in terms of elution order and resolution.The well correlated relationship between the solvation parameters and the selectivity of the CTIL and HTILs stationary phases is quite helpful in predicting and understanding the retention behaviors of different types of analytes on these stationary phases.展开更多
A guanidinium ionic liquid,N,N,N',N'-tetrahexyl-N",N"-dimethylguanidinium bis(trifluoromethane)sulfonylimide(THDMGNTf2), was synthesized and used as stationary phase for capillary gas chromatography.In compari...A guanidinium ionic liquid,N,N,N',N'-tetrahexyl-N",N"-dimethylguanidinium bis(trifluoromethane)sulfonylimide(THDMGNTf2), was synthesized and used as stationary phase for capillary gas chromatography.In comparison with imidazolium ionic liquid stationary phase,the present new stationary phase exhibits quite different selectivity and behaves more like a low polar stationary phase.The guanidinium ionic liquid of THDMG-NTf2 exhibited better separation of Grab test mixture than imidazolium ionic liquid of 1-octyl-3-butylimidazolium bis(trifluoromethane)sulfonylimide(OBIM-NTf2).Solvation parameter model was also used to evaluate the selectivity of THDMG-NTf2.Additionally,essential oil of Magnolia biondii Pamp was analyzed to further evaluate the selectivity of THDMG-NTf2 for a sample of complicated components.Satisfactory separation of the essential oil was achieved on a THDMG-NTf2 column(10 m) while using a commercial column(30 m) as reference.The present study shows that the guanidinium ionic liquid possesses novel chromatographic selectivity and has great potential for wide applications.展开更多
Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The ...Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.展开更多
Quality standardization of complementary medicine is fundamental for industry and practice as it underpins the quality,safety and efficacy of Chinese herbal medicines.Current herbal standardizations are often based on...Quality standardization of complementary medicine is fundamental for industry and practice as it underpins the quality,safety and efficacy of Chinese herbal medicines.Current herbal standardizations are often based on the quantitative analysis of a single compound,which may not reflect the total characteristic,bioactive and toxic nature of the herbs or products.Therefore,there is a need to establish an internationally recognized methodology for quality standardization of Chinese herbal medicines.The analytical methods reviewed in this article are pharmacognosy,TLC,HPLC,LCMS,CE and chemo-metrics.This article also covers the developments and applications of these methods in quality standardization.Recent advances show that a combination of these methods creates an overall chemical profile of each herb.This is supported by results reviewed in this article and obtained in our laboratory tests on medicinal herbs including Hypericum perforatum,Morinda officinalis and Centella asiatica.Significant variations in active components have been observed between herbal samples and products.It is proposed that the identification of active components,pharmacological activities and eventual clinical applications are required for a comprehensive quality standardization system.Our findings indicate that the combination of various chromatographic and chemometric methods will advance the methodology of quality standardization and enhance the overall confidence in herbal medicine for the health practitioner and the public.展开更多
As the roles of glycans in health and disease continue to be unraveled,it is becoming apparent that glycans’immense complexity cannot be ignored.To fully delineate glycan structures,we developed an integrative approa...As the roles of glycans in health and disease continue to be unraveled,it is becoming apparent that glycans’immense complexity cannot be ignored.To fully delineate glycan structures,we developed an integrative approach combining a set of cost-effective,widespread,and easy-to-handle analytical methods.The key feature of our workflow is the exploitation of a removable fluorescent label—exemplified by 9-fluorenylmethyl chloroformate(Fmoc)—to bridge the gap between diverse glycoanalytical methods,especially multiplexed capillary gel electrophoresis with laser-induced fluorescence detection(xCGELIF)and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOFMS).Through the detailed structural analysis of selected,dauntingly complex N-glycans from chicken ovalbumin,horse serum,and bovine transferrin,we illustrate the capabilities of the presented strategy.Moreover,this approach“visualizes”N-glycans that have been difficult to identify thus far—such as the sulfated glycans on human immunoglobulin A—including minute changes in glycan structures,potentially providing useful new targets for biomarker discovery.展开更多
RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist...RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist in low abundance in vivo. Here we developed an on-line trapping/capillary hydrophilic-interaction liquid chromatography/electrospray ionization-mass spectrometry(on-line trapping/cHILIC/MS) method for sensitive and simultaneous quantification of RNA modifications of N^6-methyladenosine(m^6A) and 5-methylcytosine(5-mC) from human blood. The hydrophilic organic-silica hybrid monolith was prepared using sol-gel combined with "thiol-ene" click reaction for the separation of nucleosides. A poly(MAA-co-EGDMA) monolithic capillary was used as the on-line trapping column.With the developed on-line trapping/cHILIC/MS analytical platform, the detection limits of m^6A and 5-mC can reach to 0.06 fmol and 0.10 fmol. We then investigated the contents of m^6A and 5-mC in human blood RNA from healthy persons at the age of 6-14 and 60-68 years. Our results showed that both m^6A and 5-mC contents were significantly decreased in elder persons, suggesting the RNA modifications of m^6A and 5-mC are correlated to aging.展开更多
基金the National Nature Science Foundation of China(No.20675007)
文摘The present study describes guanidinium-based ionic liquids(GBILs) as stationary phases for capillary gas chromatography (CGC) and to the best of our knowledge,no related reports are available up to now.In this study,a hexaalkylguanidinium ionic liquid(DOTMG-NTf;) was synthesized and coated statically onto capillary columns.Selectivity of the stationary phase was evaluated by separating Grob test mixture,test mixture,alcohols mixture,and fatty acid methyl esters mixture,and thermal stability was investigated as well.The present study demonstrates that GBILs as CGC stationary phases exhibit satisfactory selectivity and thermal stability and have a great potential as new candidates for CGC stationary phases.
基金Project(20235010) support by the NSFC-KOSEF Scientific Cooperation ProgramProject supported by the Program for New Century Talents of University in Henan ProvinceProgram for Backbone Teacher in Henan Province, China
文摘Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35℃ and 1.0 mL/min, respectively. Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.
基金the National Nature Science Foundation of China(No.20675007).
文摘One chloride-terminated ionic liquid(CTIL) and two hydroxyl-terminated ionic liquids(HTILs) were synthesized and used as stationary phases for capillary gas chromatography(CGC).Molecular interactions of these stationary phases were evaluated by Abraham solvation parameter model,indicating that the CTIL exhibits remarkably strong H-bond basicity and the HTILs possess both H-bond basicity and acidity.The molecular interactions were further confirmed by separation of a complex mixture consisting of ketones,aldehydes,esters,alcohols and aromatic compounds.It was found that the obtained solvation parameters correlate well with the chromatographic performances of the analytes in terms of elution order and resolution.The well correlated relationship between the solvation parameters and the selectivity of the CTIL and HTILs stationary phases is quite helpful in predicting and understanding the retention behaviors of different types of analytes on these stationary phases.
基金the National Nature Science Foundation of China(No.20675007)
文摘A guanidinium ionic liquid,N,N,N',N'-tetrahexyl-N",N"-dimethylguanidinium bis(trifluoromethane)sulfonylimide(THDMGNTf2), was synthesized and used as stationary phase for capillary gas chromatography.In comparison with imidazolium ionic liquid stationary phase,the present new stationary phase exhibits quite different selectivity and behaves more like a low polar stationary phase.The guanidinium ionic liquid of THDMG-NTf2 exhibited better separation of Grab test mixture than imidazolium ionic liquid of 1-octyl-3-butylimidazolium bis(trifluoromethane)sulfonylimide(OBIM-NTf2).Solvation parameter model was also used to evaluate the selectivity of THDMG-NTf2.Additionally,essential oil of Magnolia biondii Pamp was analyzed to further evaluate the selectivity of THDMG-NTf2 for a sample of complicated components.Satisfactory separation of the essential oil was achieved on a THDMG-NTf2 column(10 m) while using a commercial column(30 m) as reference.The present study shows that the guanidinium ionic liquid possesses novel chromatographic selectivity and has great potential for wide applications.
文摘Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.
基金supported by the International Science Linkages Australia China Special Found 2007,CH0701667established under the Australian Government's innovationstatement,Backing Australia's Ability and the University of Sydney International Program Development Fund (IDPF,2008)the China Australia Special Fund from the China National Science Fund Commission(Quality Standardisation,anti-inflammation and anti-depressant activities of Hypericum species and Morinda Officinalis,Yang Dp,2007)
文摘Quality standardization of complementary medicine is fundamental for industry and practice as it underpins the quality,safety and efficacy of Chinese herbal medicines.Current herbal standardizations are often based on the quantitative analysis of a single compound,which may not reflect the total characteristic,bioactive and toxic nature of the herbs or products.Therefore,there is a need to establish an internationally recognized methodology for quality standardization of Chinese herbal medicines.The analytical methods reviewed in this article are pharmacognosy,TLC,HPLC,LCMS,CE and chemo-metrics.This article also covers the developments and applications of these methods in quality standardization.Recent advances show that a combination of these methods creates an overall chemical profile of each herb.This is supported by results reviewed in this article and obtained in our laboratory tests on medicinal herbs including Hypericum perforatum,Morinda officinalis and Centella asiatica.Significant variations in active components have been observed between herbal samples and products.It is proposed that the identification of active components,pharmacological activities and eventual clinical applications are required for a comprehensive quality standardization system.Our findings indicate that the combination of various chromatographic and chemometric methods will advance the methodology of quality standardization and enhance the overall confidence in herbal medicine for the health practitioner and the public.
基金support from the German Federal Ministry of Education and Research(BMBF)under the project“Die Golgi Glykan Fabrik 2.0”(031A557C for Samanta Cajic and Erdmann Rapp)the European Commission(EC)under the project“HighGlycan”(278535 for RenéHennig and Erdmann Rapp)the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under the project“The concert of dolicholbased glycosylation:from molecules to disease models”(FOR2509 for Valerian Grote and Erdmann Rapp).
文摘As the roles of glycans in health and disease continue to be unraveled,it is becoming apparent that glycans’immense complexity cannot be ignored.To fully delineate glycan structures,we developed an integrative approach combining a set of cost-effective,widespread,and easy-to-handle analytical methods.The key feature of our workflow is the exploitation of a removable fluorescent label—exemplified by 9-fluorenylmethyl chloroformate(Fmoc)—to bridge the gap between diverse glycoanalytical methods,especially multiplexed capillary gel electrophoresis with laser-induced fluorescence detection(xCGELIF)and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOFMS).Through the detailed structural analysis of selected,dauntingly complex N-glycans from chicken ovalbumin,horse serum,and bovine transferrin,we illustrate the capabilities of the presented strategy.Moreover,this approach“visualizes”N-glycans that have been difficult to identify thus far—such as the sulfated glycans on human immunoglobulin A—including minute changes in glycan structures,potentially providing useful new targets for biomarker discovery.
基金financially supported by the National Natural Science Foundation of China (Nos. 21522507, 21672166, 21728802, 21721005)
文摘RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist in low abundance in vivo. Here we developed an on-line trapping/capillary hydrophilic-interaction liquid chromatography/electrospray ionization-mass spectrometry(on-line trapping/cHILIC/MS) method for sensitive and simultaneous quantification of RNA modifications of N^6-methyladenosine(m^6A) and 5-methylcytosine(5-mC) from human blood. The hydrophilic organic-silica hybrid monolith was prepared using sol-gel combined with "thiol-ene" click reaction for the separation of nucleosides. A poly(MAA-co-EGDMA) monolithic capillary was used as the on-line trapping column.With the developed on-line trapping/cHILIC/MS analytical platform, the detection limits of m^6A and 5-mC can reach to 0.06 fmol and 0.10 fmol. We then investigated the contents of m^6A and 5-mC in human blood RNA from healthy persons at the age of 6-14 and 60-68 years. Our results showed that both m^6A and 5-mC contents were significantly decreased in elder persons, suggesting the RNA modifications of m^6A and 5-mC are correlated to aging.