Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]....Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]. Organic materials, such as conducting polymers (polyacetylene, polypyrrole, polyaniline, etc.)[5], conjugated carbonyl compounds (quinone compounds, imides, etc.)[6–9] and nitroxide radical (N-O.)[10,11] compounds have been attempted as cathode materials in lithium-ion batteries (LIBs).展开更多
Chromatographic fingerprinting has been perceived as an essential tool for assessing quality and chemical equivalence of traditional Chinese medicine.However,this pattern-oriented approach still has some weak points i...Chromatographic fingerprinting has been perceived as an essential tool for assessing quality and chemical equivalence of traditional Chinese medicine.However,this pattern-oriented approach still has some weak points in terms of chemical coverage and robustness.In this work,we proposed a multiple reaction monitoring(MRM)-based fingerprinting method in which approximately 100 constituents were simultaneously detected for quality assessment.The derivative MRM approach was employed to rapidly design MRM transitions independent of chemical standards,based on which the large-scale fingerprinting method was efficiently established.This approach was exemplified on QiShenYiQi Pill(QSYQ),a traditional Chinese medicine-derived drug product,and its robustness was systematically evaluated by four indices:clustering analysis by principal component analysis,similarity analysis by the congruence coefficient,the number of separated peaks,and the peak area proportion of separated peaks.Compared with conventional ultraviolet-based fingerprints,the MRM fingerprints provided not only better discriminatory capacity for the tested normal/abnormal QSYQ samples,but also higher robustness under different chromatographic conditions(i.e.,flow rate,apparent pH,column temperature,and column).The result also showed for such large-scale fingerprints including a large number of peaks,the angle cosine measure after min-max normalization was more suitable for setting a decision criterion than the unnormalized algorithm.This proof-of-concept application gives evidence that combining MRM technique with proper similarity analysis metrices can provide a highly sensitive,robust and comprehensive analytical approach for quality assessment of traditional Chinese medicine.展开更多
Attributing to the rapid demand expansion for the edible medicinal materials in the market,the limited throughput of highperformance liquid chromatography-multiple reaction monitoring(HPLC-MRM)cannot fully address the...Attributing to the rapid demand expansion for the edible medicinal materials in the market,the limited throughput of highperformance liquid chromatography-multiple reaction monitoring(HPLC-MRM)cannot fully address the measurement workload for a huge number of testing samples.Hence,it is urgent to pursue more efficient approaches for the quality evaluation.Because of the greater selectivity of MRM cubed(MRM^(3))over MRM,there might be a chance to omit the time-intensive LC separation.In current study,we attempted to develop a direct infusion(DI)-MRM^(3) program,and the applicability was thereafter assessed through simultaneous determination of four ganoderic acids(GAs)in one of the most famous tonic herbal medicines namely Ganoderma(Chinese name:Lingzhi).Primary parameters such as Q1>Q3>QLIT ion transitions,collision energy(CE),and excitation energy were optimized by programming online energy-resolved mass spectrometry with authentic compounds.A single DI-MRM measurement merely costed four minutes,and in spite of the wide occurrences of isomers,satisfactory selectivity was achieved.Method validation assays demonstrated the method to be sensitive,precise,accurate,and reproducible.The quantitative results from DI-MRM^(3) were also justified by conducting LC-MRM measurements in parallel.Significant differences occurred for the content patterns between the two original sources namely Ganoderma lucidum and G.sinense,and,moreover,either cultivar or harvest time showed dramatical influence on the quantitative features of the four targeted GAs.More importantly,DI-MRM3 is a meaningful analytical option for rapid quantitative analysis of herbal medicines,because of the comparable reliability,nonetheless,less consumptions of both measurement time and solvent,compared with LC-MRM.展开更多
To control the stability of the lysine acetylsalicylate compound (LAS) in aqueous solution, some studies of the hydronium ion-catalyzed, hydroxide ion-catalyzed, and spontaneous reactions of this active ingredient in ...To control the stability of the lysine acetylsalicylate compound (LAS) in aqueous solution, some studies of the hydronium ion-catalyzed, hydroxide ion-catalyzed, and spontaneous reactions of this active ingredient in water solutions have been carried out. The pH-rate profile (log kobs = f(pH)), shows that the hydrolysis reaction of the LAS, is conducted by a catalysis acid-base mechanism, with multiple reaction pathways. The rate constants, kH, kOH and k0 to the reaction pathways catalyzed by H3O+, HO– ions and to the spontaneous reaction, for the hydrolysis reaction of the reagent LAS, were determined. The results show that the studied compound LAS is unstable in basic medium and the hydrolysis reaction catalyzed by HO– ions is predominant.For a known acidity (pH ≈ 10), studies conducted for different temperatures of the medium, clearly indicate, that the experimental rate constant kobs,depends on the temperature according to the Arrhenius equation. The activation parameters: activation energy (Ea), enthalpy (ΔH≠) and entropy (ΔS≠), for the transition state were determined, The very negative value obtained for the activation parameter ΔS*, first indicates that in the transition state there is gain in order, then this late state, resembles the products and that probably for the mechanism of the LAS hydrolysis reaction catalyzed by HO– ions, the rate-determining step is a bimolecular reaction. Finally from all these results, the mechanism for the reaction pathway catalyzed by HO– ions has been elucidated.展开更多
The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam.By strategically using the in situ generated Appel’s salt or Mitsunobu’s zwitterionic adduct as the de-hydrating agent,...The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam.By strategically using the in situ generated Appel’s salt or Mitsunobu’s zwitterionic adduct as the de-hydrating agent,a series of Beckmann rearrangement and following cascade reactions have been devel-oped herein.The protocol allows the conversion of various ketoximes into amide,thioamide,tetrazole and imide products in modular procedures.The generality and tolerance of functionalities of this method have been demonstrated.展开更多
Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the...Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the present study,a novel method for the determination of 14 PASHs in PM_(2.5) was developed using atmospheric pressure gas chro matography-tandem mass spectrometry(APGC-MS/MS).Atmospheric pressure chemical ionization was operated with multiple reaction monitoring in positive ionization mode.High sensitivity(method detection limit <1.673 pg/m^(3)),acceptable re coveries(67.6%-120.8%) and precisions(RSD of 2.2%-15.4%) were obtained.The method was successfully applied for analyzing PASHs in 10 PM_(2.5) samples collected from Taiyuan,a typical industrial city in China,in 2016,The total concentrations were from 929 pg/m^(3) to 14,593 pg/m^(3).The determined levels indicated that further investigations on environmental fate and toxicities of PM_(2.5)-bound PASHs may be needed.展开更多
Objective:To establish a reliable and sensitive method for evaluating quality of Yiqi Jiangzhi Granules(YQJZG).Methods:Ultra performance liquid chromatography electrospray ionization tandem mass spectrometry(UPLC-ESI-...Objective:To establish a reliable and sensitive method for evaluating quality of Yiqi Jiangzhi Granules(YQJZG).Methods:Ultra performance liquid chromatography electrospray ionization tandem mass spectrometry(UPLC-ESI-MS/MS)was employed for simultaneous determination of eight marker components.Separation was performed on an AQUITY UPLC;HSS T3 column,the mobile phase consisted of acetonitrile as the organic phase and 0.1%(volume percentage)formic acid as the aqueous.Eight marker components,ginsenoside Rg1(GRg1),ginsenoside Re(GRe),ginsenoside Rb1(Gb1),typhaneoside(TEO),isorhamnetin-3-O-neohespeidoside(IN),hesperidin(HPD),aurantio-obtusin-6-O-β-D-glucoside(AG)and curcumin(CCM),were detected by multiple reaction monitoring(MRM)mode.The Chinese Pharmacopoeia(2020 edition)was regarded as the guidance document for this method validation.Results:The method showed good linearity(R^(2)≥0.9990).The relative standard deviation(RSD)values for the instrument precision,intermediate precision and repeatability were less than 2.91%,2.88%,and 3.54%,respectively.The average recovery varied from 91.08%to 103.89%,with RSD below 3.81%.Sample solutions were found to be stable within 24 h at 4℃(RSD<2.85%).Eight marker components were successfully determined from three batches of YQJZG.Conclusion:The proposed UPLC-ESI-MS/MS method was found to be simple,fast and sensitive,and can be used for the routine quality assessment of YQJZG.Simultaneously,this method may provide a new and powerful tool of quality control for other traditional Chinese medicine analogous formulae.展开更多
The presence of pesticide residues in food and vegetables is a growing concern for consumers.To monitor these residues reliably,a selective and sensitive multiresidue system has been developed and validated in tomato ...The presence of pesticide residues in food and vegetables is a growing concern for consumers.To monitor these residues reliably,a selective and sensitive multiresidue system has been developed and validated in tomato by gas chromatography–tandem mass spectrometry(GC-MS/MS).Titanium-coated graphite with carbon nanotube(CNT)in acrylonitrile–butadiene–styrene(ABS)used as reversed-dispersive solid-phase extraction materials with modified QuEChERS(Quick,Easy,Cheap,Effective,Rugged,and Safe)method.Titanium-coated graphite with CNT-ABS is synthesized,characterized by X-ray diffraction and scanning electron microscopy.The clean-up performance of titanium-coated graphite with CNT-ABS was demonstrated to be better to primary secondary amine and graphitized carbon black cartridges.The processing of two multiple reaction monitoring transformations for each analyte is done using GC-MS/MS in electron impact mode.Satisfactory purification and recovery effects(74%–100%)of 35 pesticides were achieved in tomato matrices when using 5 mg of titanium-coated graphite ABS-CNT nanocomposite.It was observed that quinolphos and deltamethrin are present above the maximum residue limit.The technique proved to be reliable and sensitive in tomato samples for the routine testing of 35 pesticides.展开更多
基金financially supported by the National Key R&D Program of China(2017YFA0206700)the National Natural Science Foundation of China(grant No.21822506&51671107)+1 种基金the 111 project of B12015the Natural Science Foundation of Tianjin(grant No.19JCJQJC62400)。
文摘Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]. Organic materials, such as conducting polymers (polyacetylene, polypyrrole, polyaniline, etc.)[5], conjugated carbonyl compounds (quinone compounds, imides, etc.)[6–9] and nitroxide radical (N-O.)[10,11] compounds have been attempted as cathode materials in lithium-ion batteries (LIBs).
基金financially supported by the National Natural Science Foundation of China(Grant No.81803714)the Fundamental Research Funds for the Central Universities(Grant No.2019QNA7041).
文摘Chromatographic fingerprinting has been perceived as an essential tool for assessing quality and chemical equivalence of traditional Chinese medicine.However,this pattern-oriented approach still has some weak points in terms of chemical coverage and robustness.In this work,we proposed a multiple reaction monitoring(MRM)-based fingerprinting method in which approximately 100 constituents were simultaneously detected for quality assessment.The derivative MRM approach was employed to rapidly design MRM transitions independent of chemical standards,based on which the large-scale fingerprinting method was efficiently established.This approach was exemplified on QiShenYiQi Pill(QSYQ),a traditional Chinese medicine-derived drug product,and its robustness was systematically evaluated by four indices:clustering analysis by principal component analysis,similarity analysis by the congruence coefficient,the number of separated peaks,and the peak area proportion of separated peaks.Compared with conventional ultraviolet-based fingerprints,the MRM fingerprints provided not only better discriminatory capacity for the tested normal/abnormal QSYQ samples,but also higher robustness under different chromatographic conditions(i.e.,flow rate,apparent pH,column temperature,and column).The result also showed for such large-scale fingerprints including a large number of peaks,the angle cosine measure after min-max normalization was more suitable for setting a decision criterion than the unnormalized algorithm.This proof-of-concept application gives evidence that combining MRM technique with proper similarity analysis metrices can provide a highly sensitive,robust and comprehensive analytical approach for quality assessment of traditional Chinese medicine.
基金financially supported by the National Natural Science Foundation of China(81973444)the Open Research Project Programme of the State Key Laboratory of Quality Research in Chinese Medicine(University of Macao)(SKLQRCM-OP21011).
文摘Attributing to the rapid demand expansion for the edible medicinal materials in the market,the limited throughput of highperformance liquid chromatography-multiple reaction monitoring(HPLC-MRM)cannot fully address the measurement workload for a huge number of testing samples.Hence,it is urgent to pursue more efficient approaches for the quality evaluation.Because of the greater selectivity of MRM cubed(MRM^(3))over MRM,there might be a chance to omit the time-intensive LC separation.In current study,we attempted to develop a direct infusion(DI)-MRM^(3) program,and the applicability was thereafter assessed through simultaneous determination of four ganoderic acids(GAs)in one of the most famous tonic herbal medicines namely Ganoderma(Chinese name:Lingzhi).Primary parameters such as Q1>Q3>QLIT ion transitions,collision energy(CE),and excitation energy were optimized by programming online energy-resolved mass spectrometry with authentic compounds.A single DI-MRM measurement merely costed four minutes,and in spite of the wide occurrences of isomers,satisfactory selectivity was achieved.Method validation assays demonstrated the method to be sensitive,precise,accurate,and reproducible.The quantitative results from DI-MRM^(3) were also justified by conducting LC-MRM measurements in parallel.Significant differences occurred for the content patterns between the two original sources namely Ganoderma lucidum and G.sinense,and,moreover,either cultivar or harvest time showed dramatical influence on the quantitative features of the four targeted GAs.More importantly,DI-MRM3 is a meaningful analytical option for rapid quantitative analysis of herbal medicines,because of the comparable reliability,nonetheless,less consumptions of both measurement time and solvent,compared with LC-MRM.
文摘To control the stability of the lysine acetylsalicylate compound (LAS) in aqueous solution, some studies of the hydronium ion-catalyzed, hydroxide ion-catalyzed, and spontaneous reactions of this active ingredient in water solutions have been carried out. The pH-rate profile (log kobs = f(pH)), shows that the hydrolysis reaction of the LAS, is conducted by a catalysis acid-base mechanism, with multiple reaction pathways. The rate constants, kH, kOH and k0 to the reaction pathways catalyzed by H3O+, HO– ions and to the spontaneous reaction, for the hydrolysis reaction of the reagent LAS, were determined. The results show that the studied compound LAS is unstable in basic medium and the hydrolysis reaction catalyzed by HO– ions is predominant.For a known acidity (pH ≈ 10), studies conducted for different temperatures of the medium, clearly indicate, that the experimental rate constant kobs,depends on the temperature according to the Arrhenius equation. The activation parameters: activation energy (Ea), enthalpy (ΔH≠) and entropy (ΔS≠), for the transition state were determined, The very negative value obtained for the activation parameter ΔS*, first indicates that in the transition state there is gain in order, then this late state, resembles the products and that probably for the mechanism of the LAS hydrolysis reaction catalyzed by HO– ions, the rate-determining step is a bimolecular reaction. Finally from all these results, the mechanism for the reaction pathway catalyzed by HO– ions has been elucidated.
基金supported by National Key Research and Development Project (No. 2021YFC2100100)National Natural Science Foundation of China (No. 21901123)+1 种基金Natural Science Foundation of Jiangsu Province (No. BK20190694)Jiangsu Specially Appointed Professor Plan
文摘The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam.By strategically using the in situ generated Appel’s salt or Mitsunobu’s zwitterionic adduct as the de-hydrating agent,a series of Beckmann rearrangement and following cascade reactions have been devel-oped herein.The protocol allows the conversion of various ketoximes into amide,thioamide,tetrazole and imide products in modular procedures.The generality and tolerance of functionalities of this method have been demonstrated.
基金financial support from the National Natural Science Foundation of China (Nos.91843301 and 91543202)National Key Research and Development Program Cooperation on Scientific and Technological Innovation in Hong Kong,Macao and Taiwan (No. 2017YFE0191000)。
文摘Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the present study,a novel method for the determination of 14 PASHs in PM_(2.5) was developed using atmospheric pressure gas chro matography-tandem mass spectrometry(APGC-MS/MS).Atmospheric pressure chemical ionization was operated with multiple reaction monitoring in positive ionization mode.High sensitivity(method detection limit <1.673 pg/m^(3)),acceptable re coveries(67.6%-120.8%) and precisions(RSD of 2.2%-15.4%) were obtained.The method was successfully applied for analyzing PASHs in 10 PM_(2.5) samples collected from Taiyuan,a typical industrial city in China,in 2016,The total concentrations were from 929 pg/m^(3) to 14,593 pg/m^(3).The determined levels indicated that further investigations on environmental fate and toxicities of PM_(2.5)-bound PASHs may be needed.
基金supported by the Natural Science Foundation of Beijing Municipality(No.7192117)。
文摘Objective:To establish a reliable and sensitive method for evaluating quality of Yiqi Jiangzhi Granules(YQJZG).Methods:Ultra performance liquid chromatography electrospray ionization tandem mass spectrometry(UPLC-ESI-MS/MS)was employed for simultaneous determination of eight marker components.Separation was performed on an AQUITY UPLC;HSS T3 column,the mobile phase consisted of acetonitrile as the organic phase and 0.1%(volume percentage)formic acid as the aqueous.Eight marker components,ginsenoside Rg1(GRg1),ginsenoside Re(GRe),ginsenoside Rb1(Gb1),typhaneoside(TEO),isorhamnetin-3-O-neohespeidoside(IN),hesperidin(HPD),aurantio-obtusin-6-O-β-D-glucoside(AG)and curcumin(CCM),were detected by multiple reaction monitoring(MRM)mode.The Chinese Pharmacopoeia(2020 edition)was regarded as the guidance document for this method validation.Results:The method showed good linearity(R^(2)≥0.9990).The relative standard deviation(RSD)values for the instrument precision,intermediate precision and repeatability were less than 2.91%,2.88%,and 3.54%,respectively.The average recovery varied from 91.08%to 103.89%,with RSD below 3.81%.Sample solutions were found to be stable within 24 h at 4℃(RSD<2.85%).Eight marker components were successfully determined from three batches of YQJZG.Conclusion:The proposed UPLC-ESI-MS/MS method was found to be simple,fast and sensitive,and can be used for the routine quality assessment of YQJZG.Simultaneously,this method may provide a new and powerful tool of quality control for other traditional Chinese medicine analogous formulae.
文摘The presence of pesticide residues in food and vegetables is a growing concern for consumers.To monitor these residues reliably,a selective and sensitive multiresidue system has been developed and validated in tomato by gas chromatography–tandem mass spectrometry(GC-MS/MS).Titanium-coated graphite with carbon nanotube(CNT)in acrylonitrile–butadiene–styrene(ABS)used as reversed-dispersive solid-phase extraction materials with modified QuEChERS(Quick,Easy,Cheap,Effective,Rugged,and Safe)method.Titanium-coated graphite with CNT-ABS is synthesized,characterized by X-ray diffraction and scanning electron microscopy.The clean-up performance of titanium-coated graphite with CNT-ABS was demonstrated to be better to primary secondary amine and graphitized carbon black cartridges.The processing of two multiple reaction monitoring transformations for each analyte is done using GC-MS/MS in electron impact mode.Satisfactory purification and recovery effects(74%–100%)of 35 pesticides were achieved in tomato matrices when using 5 mg of titanium-coated graphite ABS-CNT nanocomposite.It was observed that quinolphos and deltamethrin are present above the maximum residue limit.The technique proved to be reliable and sensitive in tomato samples for the routine testing of 35 pesticides.
