Polygonati rhizoma is often used in Chinese medicine and as food.In this study,atmospheric pressure matrixassisted laser desorption ionization and quadruple-time-of-flight(MALDI-Q-TOF)mass spectrometry techniques were...Polygonati rhizoma is often used in Chinese medicine and as food.In this study,atmospheric pressure matrixassisted laser desorption ionization and quadruple-time-of-flight(MALDI-Q-TOF)mass spectrometry techniques were applied to P.rhizoma samples from Polygonatum cyrtonema Hua species.Positive ions were mainly detected in the mass range of m/z 200-600,while negative ions were mainly observed in the mass range of m/z 100-450.A total of 263 components were identified and the spatial distribution and changes in saccharides contents during the steaming process of P.rhizoma were investigated.Monosaccharide and disaccharide exhibit a relatively uniform distribution,while the oligosaccharides were mainly found in the bast of fresh P.rhizoma.Although the contents of monosaccharide and disaccharide were increased during steaming,that of trisaccharide,tetrasaccharide,and pentasaccharide were decreased.We used the 5 saccharide types with the greatest variation in content as variables for the principal component analysis(PCA)and cluster analysis.Both PCA and cluster analysis showed that these 5 saccharides can be used as markers in the steaming process of the P.rhizoma.Present study of mass spectrometry imaging provides novel insights into the spatiotemporal accumulation patterns of saccharides in P.rhizoma,improving our understanding of the steaming process.展开更多
The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides...The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.展开更多
The current study comprehensively evaluates four different protein extraction methods based on urea,sodium dodecyl sulfate(SDS),anionic surfactants(BT),and total RNA extractor(Trizol),aiming to optimize the sample pre...The current study comprehensively evaluates four different protein extraction methods based on urea,sodium dodecyl sulfate(SDS),anionic surfactants(BT),and total RNA extractor(Trizol),aiming to optimize the sample preparation workflow for mass spectrometry-based proteomics.Using HeLa cells as an example,we found that the method employing the mass spectrometry-compatible surfactant BT reagent significantly reduces the total time consumed for protein extraction and minimizes protein losses during the sample preparation process.Further integrating the four protein extraction methods,we identified over 7000 proteins from HeLa cells without relying on pre-fractionation techniques,and 2990 of them were quantified using label-free quantification.It is worth noting that the BT and SDS methods demonstrate higher efficiency in extracting membrane proteins,while the Urea and Trizol methods are more effective in extracting proteins from nuclear and cytoplasmic fractions.In summary,this study provides a novel solution for deep proteome coverage,particularly in the context of cellular protein extraction,by integrating mass spectrometry-compatible surfactants with traditional extraction methods to effectively enhance protein identification numbers.展开更多
In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.Ho...In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.展开更多
Profiling the protein composition of bacteria is essential for understanding their biology,physiology and interaction with environment.Mass spectrometry has become a pivotal tool for protein analysis,facilitating the ...Profiling the protein composition of bacteria is essential for understanding their biology,physiology and interaction with environment.Mass spectrometry has become a pivotal tool for protein analysis,facilitating the examination of expression levels,molecular masses and structural modifications.In this study,we compared the performance of three widely-used mass spectrometry methods,i.e.,matrix-assisted laser desorption/ionization(MALDI)protein fingerprinting,top-down proteomics and bottom-up proteomics,in the profiling of bacterial protein composition.It was revealed that bottom-up proteomics provided the highest protein coverage and exhibited the greatest protein profile overlap between bacterial species.In contrast,MALDI protein fingerprinting demonstrated superior detection reproducibility and effectiveness in distinguishing between bacterial species.Although top-down proteomics identified fewer proteins than bottom-up approach,it complemented MALDI fingerprinting in the discovery of bacterial protein markers,both favoring abundant,stable,and hydrophilic bacterial ribosomal proteins.This study represents the most systematic and comprehensive comparison of mass spectrometry-based protein profiling methodologies to date.It provides valuable guidelines for the selection of appropriate profiling strategies for specific analytical purposes.This will facilitate studies across various fields,including infection diagnosis,antimicrobial resistance detection and pharmaceutical target discovery.展开更多
The primary impediment to the recovery of heavy oil lies in its high viscosity, which necessitates a deeper understanding of the molecular mechanisms governing its dynamic behavior for enhanced oil recovery. However, ...The primary impediment to the recovery of heavy oil lies in its high viscosity, which necessitates a deeper understanding of the molecular mechanisms governing its dynamic behavior for enhanced oil recovery. However, there remains a dearth of understanding regarding the complex molecular composition inherent to heavy oil. In this study, we employed high-resolution mass spectrometry in conjunction with various chemical derivatization and ionization methods to obtain semi-quantitative results of molecular group compositions of 35 heavy oils. The gradient boosting(GB) model has been further used to acquire the feature importance rank(FIR). A feature is an independently observable property of the observed object. Feature importance can measure the contribution of each input feature to the model prediction result, indicate the degree of correlation between the feature and the target,unveil which features are indicative of certain predictions. We have developed a framework for utilizing physical insights into the impact of molecular group compositions on viscosity. The results of machine learning(ML) conducted by GB show that the viscosity of heavy oils is primarily influenced by light components, specifically small molecular hydrocarbons with low condensation degrees, as well as petroleum acids composed of acidic oxygen groups and neutral nitrogen groups. Additionally, large molecular aromatic hydrocarbons and sulfoxides also play significant roles in determine the viscosity.展开更多
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
This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in ...This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for ^(241)Am emitting lowenergy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.展开更多
The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tande...The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.展开更多
Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution ...Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution times of the ions stored in the ring.However,the revolution times cannot be resolved for particles with nearly the same mass-to-charge(m/q)ratios.To overcome this limitation and to extract the accurate revolution times for such pairs of ion species with very close m/q ratios,in our early work on particle identification,we analyzed the amplitudes of the timing signals from the detector based on the emission of secondary electrons.Here,the previous data analysis method is further improved by considering the signal amplitudes,detection efficiencies,and number of stored ions in the ring.A sensitive Z-dependent parameter is introduced in the data analysis,leading to a better resolution of ^(34)Ar^(18+) and ^(51)Co^(27+) with A/Z=17/9.The mean revolution times of ^(34)Ar^(18+) and ^(51)Co^(27+) are deduced,although their time difference is merely 1.8 ps.The uncorrected,overlapped peak of these ions has a full width at half maximum of 7.7 ps.The mass excess of ^(51)Co was determined to be-27;332e41T keV,which is in agreement with the previous value of-27;342e48T keV.展开更多
The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples...The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.展开更多
Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-...Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.展开更多
In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purificatio...In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.展开更多
Objective To investigate the feasibility of analyzing acylcarnitine in dry filter-paper blood spots by liquid chromatography-tandem mass spectrometry(LC-MS/MS) which could be applied to detect inborn errors of metabol...Objective To investigate the feasibility of analyzing acylcarnitine in dry filter-paper blood spots by liquid chromatography-tandem mass spectrometry(LC-MS/MS) which could be applied to detect inborn errors of metabolism in neonates.Methods We obtained filter-paper blood from 26 dead infants from a neonatal intensive care unit(NICU) between October 1,2008 and September 30,2009.Acylcarnitine and amino acid profiles were obtained with LC-MS/MS.Four infants underwent routine autopsy.The postmortem blood specimens were compared with newborn blood specimens,and with specimens obtained from older infants with metabolic disorders.Results Of all the 26 patients,5(19.2%) were diagnosed as having different kinds of diseases:3 with methylmalonic acidemia(the concentration of C3,and the ratio of C3/C16,C3/C2 increased),1 with maple syrup urine disease(the concentration of leucine and isoleucine increased),and 1 with isovaleric aci-demia(the concentration of C5 increased).Conclusions Postmortem metabolic test can explain infant deaths and provide estimates of deaths attributable to inborn errors of metabolism in NICU.LC-MS/MS is suitable for analysis of postmortem specimens and can be considered for routine application in NICU autopsy.展开更多
High oleic-acid peanuts are known for their pre-longed shelf-life and health benefit due to high content of oleic fatty acid.However,the allergenicity and allergenic protein profiles in Chinese high-oleic peanuts have...High oleic-acid peanuts are known for their pre-longed shelf-life and health benefit due to high content of oleic fatty acid.However,the allergenicity and allergenic protein profiles in Chinese high-oleic peanuts have yet to be studied.For this purpose,an Orbitrap Fusion mass spectrometry(MS)-based method that is feasible for identification of putative allergenic protein as well as semi-quantitation of five major allergen protein in three different Chinese high-oleic peanut cultivars(JH 13,JH 16 and JH 18)have been reported.Results show that three Chinese high-oleic acid peanut cultivars selected all contained highly allergenic proteins Ara h1,Ara h 2,Ara h 3 and Ara h 6.The allergenic protein profiles of Chinese high-oleic acid peanut cultivars were very similar to that of conventional peanuts,but the allergenic protein subunits varied greatly among higholeic peanuts.Additionally,a comprehensive peptide-filtering pipeline had been developed for identification of potential peptide markers in peanut allergen proteins.Through the peptide-filtering pipeline,three novel peptide markers,IVQIEAKPNTLVLPK,SSNPDIYNPQAGSLR and AQSENYEYLAFK surrogate to Ara h 1,Ara h 3 with high abundance,good MS response and highly reliability were identified,which can be used as candidate peptide markers for the detection of peanut allergens in different food matrices.展开更多
In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation cou...In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation counter,volume,and energy res-olution of scintillation crystals,and flight altitude of an aircraft was investigated.To verify this theory,experi-mental devices based on NaI and CeBr 3 scintillation counters were prepared,and the potassium,uranium,and thorium contents in calibration pads obtained via the stripping ratio method and theory were compared.The MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo method.The relative errors found via a comparison of the experimental and theoretical results were less than 4%.The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.展开更多
Non-thermal C/H/Ar plasmas are widely applied to carbonaceous material production and processing.In this work,plasma parameters and gaseous species of the atmospheric non-thermal C/H/Ar plasmas produced by an atmosphe...Non-thermal C/H/Ar plasmas are widely applied to carbonaceous material production and processing.In this work,plasma parameters and gaseous species of the atmospheric non-thermal C/H/Ar plasmas produced by an atmospheric-pressure DC arc discharge generator in CH_4/Ar were investigated.The voltage-current characteristics were measured for different CH_4/Ar ratios.Optical emission spectroscopy was employed to analyze the electron excitation temperature,gas temperature and electron density under various discharge conditions.The hydrocarbon molecules produced in the CH4/Ar plasmas were detected with photoionization mass spectrometry.The optical spectral results demonstrated that the electron excitation temperature was 0.4-1 eV,the gas temperature was 2800-4200 K and the electron density was in the range of（5-20）×10^15 cm^-3.The mass spectrum indicated that a variety of unsaturated hydrocarbons（C2H4,C3H6,C6H6,etc.） and several highly unsaturated hydrocarbons（C4H2,C5H6,etc.） were produced in the non-thermal arc plasmas.展开更多
Nutriology relies on advanced analytical tools to study the molecular compositions of food and provide key information on sample quality/safety. Small nutrients detection is challenging due to the high diversity and b...Nutriology relies on advanced analytical tools to study the molecular compositions of food and provide key information on sample quality/safety. Small nutrients detection is challenging due to the high diversity and broad dynamic range of molecules in food samples, and a further issue is to track low abundance toxins. Herein, we developed a novel plasmonic matrix-assisted laser desorption/ionization mass spectrometry(MALDI MS)approach to detect small nutrients and toxins in complex biological emulsion samples. Silver nanoshells(SiO_2@-Ag) with optimized structures were used as matrices andachieved direct analysis of ~ 6 n L of human breast milk without any enrichment or separation. We performed identification and quantitation of small nutrients and toxins with limit-of-detection down to 0.4 pmol(for melamine) and reaction time shortened to minutes, which is superior to the conventional biochemical method currently in use. The developed approach contributes to the near-future application of MALDI MS in a broad field and personalized design of plasmonic materials for real-case bio-analysis.展开更多
Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In t...Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.展开更多
Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alterna...Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.展开更多
基金funded by the Science and Technology Innovation Program of Hunan Province(2022RC1224,2022ZYC010)the Changsha Science and Technology Program(kh2004018)the Training Program for Excellent Young Innovators of Changsha(kq2206064)。
文摘Polygonati rhizoma is often used in Chinese medicine and as food.In this study,atmospheric pressure matrixassisted laser desorption ionization and quadruple-time-of-flight(MALDI-Q-TOF)mass spectrometry techniques were applied to P.rhizoma samples from Polygonatum cyrtonema Hua species.Positive ions were mainly detected in the mass range of m/z 200-600,while negative ions were mainly observed in the mass range of m/z 100-450.A total of 263 components were identified and the spatial distribution and changes in saccharides contents during the steaming process of P.rhizoma were investigated.Monosaccharide and disaccharide exhibit a relatively uniform distribution,while the oligosaccharides were mainly found in the bast of fresh P.rhizoma.Although the contents of monosaccharide and disaccharide were increased during steaming,that of trisaccharide,tetrasaccharide,and pentasaccharide were decreased.We used the 5 saccharide types with the greatest variation in content as variables for the principal component analysis(PCA)and cluster analysis.Both PCA and cluster analysis showed that these 5 saccharides can be used as markers in the steaming process of the P.rhizoma.Present study of mass spectrometry imaging provides novel insights into the spatiotemporal accumulation patterns of saccharides in P.rhizoma,improving our understanding of the steaming process.
基金supported by the National Natural Science Foundation of China(Nos.12125509,12222514,11961141003,and 12005304)National Key Research and Development Project(No.2022YFA1602301)+1 种基金CAST Young Talent Support Planthe CNNC Science Fund for Talented Young Scholars Continuous support for basic scientific research projects。
文摘The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.
文摘The current study comprehensively evaluates four different protein extraction methods based on urea,sodium dodecyl sulfate(SDS),anionic surfactants(BT),and total RNA extractor(Trizol),aiming to optimize the sample preparation workflow for mass spectrometry-based proteomics.Using HeLa cells as an example,we found that the method employing the mass spectrometry-compatible surfactant BT reagent significantly reduces the total time consumed for protein extraction and minimizes protein losses during the sample preparation process.Further integrating the four protein extraction methods,we identified over 7000 proteins from HeLa cells without relying on pre-fractionation techniques,and 2990 of them were quantified using label-free quantification.It is worth noting that the BT and SDS methods demonstrate higher efficiency in extracting membrane proteins,while the Urea and Trizol methods are more effective in extracting proteins from nuclear and cytoplasmic fractions.In summary,this study provides a novel solution for deep proteome coverage,particularly in the context of cellular protein extraction,by integrating mass spectrometry-compatible surfactants with traditional extraction methods to effectively enhance protein identification numbers.
基金supported in part by the National Key R&D Program of China (No. 2023YFA1606401)CAS Project for Young Scientists in Basic Research (No. YSBR-002)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB34000000)the NSFC (Nos. 12305126, 12135017, 12121005)the support from the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2021419)the support from the Yong Scholar of Regional Development,CAS (No.[2023]15)
文摘In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.
文摘Profiling the protein composition of bacteria is essential for understanding their biology,physiology and interaction with environment.Mass spectrometry has become a pivotal tool for protein analysis,facilitating the examination of expression levels,molecular masses and structural modifications.In this study,we compared the performance of three widely-used mass spectrometry methods,i.e.,matrix-assisted laser desorption/ionization(MALDI)protein fingerprinting,top-down proteomics and bottom-up proteomics,in the profiling of bacterial protein composition.It was revealed that bottom-up proteomics provided the highest protein coverage and exhibited the greatest protein profile overlap between bacterial species.In contrast,MALDI protein fingerprinting demonstrated superior detection reproducibility and effectiveness in distinguishing between bacterial species.Although top-down proteomics identified fewer proteins than bottom-up approach,it complemented MALDI fingerprinting in the discovery of bacterial protein markers,both favoring abundant,stable,and hydrophilic bacterial ribosomal proteins.This study represents the most systematic and comprehensive comparison of mass spectrometry-based protein profiling methodologies to date.It provides valuable guidelines for the selection of appropriate profiling strategies for specific analytical purposes.This will facilitate studies across various fields,including infection diagnosis,antimicrobial resistance detection and pharmaceutical target discovery.
基金supported by the National Key R&D Program of China (2018YFA0702400)。
文摘The primary impediment to the recovery of heavy oil lies in its high viscosity, which necessitates a deeper understanding of the molecular mechanisms governing its dynamic behavior for enhanced oil recovery. However, there remains a dearth of understanding regarding the complex molecular composition inherent to heavy oil. In this study, we employed high-resolution mass spectrometry in conjunction with various chemical derivatization and ionization methods to obtain semi-quantitative results of molecular group compositions of 35 heavy oils. The gradient boosting(GB) model has been further used to acquire the feature importance rank(FIR). A feature is an independently observable property of the observed object. Feature importance can measure the contribution of each input feature to the model prediction result, indicate the degree of correlation between the feature and the target,unveil which features are indicative of certain predictions. We have developed a framework for utilizing physical insights into the impact of molecular group compositions on viscosity. The results of machine learning(ML) conducted by GB show that the viscosity of heavy oils is primarily influenced by light components, specifically small molecular hydrocarbons with low condensation degrees, as well as petroleum acids composed of acidic oxygen groups and neutral nitrogen groups. Additionally, large molecular aromatic hydrocarbons and sulfoxides also play significant roles in determine the viscosity.
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.
基金supported by the Support Program of the Ministry of Science and Technology(No.2014FY211000)the National Key Technology Research and Development Program(No.2013BAK03B05)
文摘This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for ^(241)Am emitting lowenergy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.
文摘The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.
基金This work was supported by the National Key R&D Program of China(Nos.2016YFA0400504 and 2018YFA0404401)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34000000)+4 种基金the National Natural Science Foundation of China(Nos.11905261,11805032,11975280,and 11605248)the CAS "Light of West China" Program,the China Postdoctoral Science Foundation(No.2019M660250)the FRIB-CSC Fellowship,China(No.201704910964)the International Postdoctoral Exchange Fellowship Program 2017 by the Office of China Postdoctoral Council(No.60 Document of OCPC,2017)the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Programme(No.682841 "ASTRUm").
文摘Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution times of the ions stored in the ring.However,the revolution times cannot be resolved for particles with nearly the same mass-to-charge(m/q)ratios.To overcome this limitation and to extract the accurate revolution times for such pairs of ion species with very close m/q ratios,in our early work on particle identification,we analyzed the amplitudes of the timing signals from the detector based on the emission of secondary electrons.Here,the previous data analysis method is further improved by considering the signal amplitudes,detection efficiencies,and number of stored ions in the ring.A sensitive Z-dependent parameter is introduced in the data analysis,leading to a better resolution of ^(34)Ar^(18+) and ^(51)Co^(27+) with A/Z=17/9.The mean revolution times of ^(34)Ar^(18+) and ^(51)Co^(27+) are deduced,although their time difference is merely 1.8 ps.The uncorrected,overlapped peak of these ions has a full width at half maximum of 7.7 ps.The mass excess of ^(51)Co was determined to be-27;332e41T keV,which is in agreement with the previous value of-27;342e48T keV.
基金This work was supported by“National Key Research and Development Program of China”(Project No.2018YFC1603400)Science and Technology Program of Hebei Province(Project No.19225503D).
文摘The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.
基金supported by Natural Science Foundation of China(32072633,32072634,31201335)earmarked fund for China Agriculture Research System(CARS-19)+1 种基金Anhui Key research and development plan(1804b06020367,202004b11020004)Young Elite Scientist Sponsorship Program by National CAST(2016QNRC001)。
文摘Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.
基金National Key Research and Development Program of China(Project No.2018YFC1603400)Science and Technology Program of Hebei Province(Project No.19225503D)Technical Support Project of State Administration for Market Regulation(Project No.2019YJ009).
文摘In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.
文摘Objective To investigate the feasibility of analyzing acylcarnitine in dry filter-paper blood spots by liquid chromatography-tandem mass spectrometry(LC-MS/MS) which could be applied to detect inborn errors of metabolism in neonates.Methods We obtained filter-paper blood from 26 dead infants from a neonatal intensive care unit(NICU) between October 1,2008 and September 30,2009.Acylcarnitine and amino acid profiles were obtained with LC-MS/MS.Four infants underwent routine autopsy.The postmortem blood specimens were compared with newborn blood specimens,and with specimens obtained from older infants with metabolic disorders.Results Of all the 26 patients,5(19.2%) were diagnosed as having different kinds of diseases:3 with methylmalonic acidemia(the concentration of C3,and the ratio of C3/C16,C3/C2 increased),1 with maple syrup urine disease(the concentration of leucine and isoleucine increased),and 1 with isovaleric aci-demia(the concentration of C5 increased).Conclusions Postmortem metabolic test can explain infant deaths and provide estimates of deaths attributable to inborn errors of metabolism in NICU.LC-MS/MS is suitable for analysis of postmortem specimens and can be considered for routine application in NICU autopsy.
基金supported by the China National Key R&D Program during the 13th Five-year Plan Period(2019YFC1605004)。
文摘High oleic-acid peanuts are known for their pre-longed shelf-life and health benefit due to high content of oleic fatty acid.However,the allergenicity and allergenic protein profiles in Chinese high-oleic peanuts have yet to be studied.For this purpose,an Orbitrap Fusion mass spectrometry(MS)-based method that is feasible for identification of putative allergenic protein as well as semi-quantitation of five major allergen protein in three different Chinese high-oleic peanut cultivars(JH 13,JH 16 and JH 18)have been reported.Results show that three Chinese high-oleic acid peanut cultivars selected all contained highly allergenic proteins Ara h1,Ara h 2,Ara h 3 and Ara h 6.The allergenic protein profiles of Chinese high-oleic acid peanut cultivars were very similar to that of conventional peanuts,but the allergenic protein subunits varied greatly among higholeic peanuts.Additionally,a comprehensive peptide-filtering pipeline had been developed for identification of potential peptide markers in peanut allergen proteins.Through the peptide-filtering pipeline,three novel peptide markers,IVQIEAKPNTLVLPK,SSNPDIYNPQAGSLR and AQSENYEYLAFK surrogate to Ara h 1,Ara h 3 with high abundance,good MS response and highly reliability were identified,which can be used as candidate peptide markers for the detection of peanut allergens in different food matrices.
基金This work was supported by the Sichuan Science and Technology Program(No.2020JDRC0108)the National Science Foundation of China(Nos.41774147 and 41774190).
文摘In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation counter,volume,and energy res-olution of scintillation crystals,and flight altitude of an aircraft was investigated.To verify this theory,experi-mental devices based on NaI and CeBr 3 scintillation counters were prepared,and the potassium,uranium,and thorium contents in calibration pads obtained via the stripping ratio method and theory were compared.The MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo method.The relative errors found via a comparison of the experimental and theoretical results were less than 4%.The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.
基金supported by National Natural Science Foundation of China(Nos.11035005,11475174,50876101)USTC-NSRL Association Funding(No.KY2090130001)
文摘Non-thermal C/H/Ar plasmas are widely applied to carbonaceous material production and processing.In this work,plasma parameters and gaseous species of the atmospheric non-thermal C/H/Ar plasmas produced by an atmospheric-pressure DC arc discharge generator in CH_4/Ar were investigated.The voltage-current characteristics were measured for different CH_4/Ar ratios.Optical emission spectroscopy was employed to analyze the electron excitation temperature,gas temperature and electron density under various discharge conditions.The hydrocarbon molecules produced in the CH4/Ar plasmas were detected with photoionization mass spectrometry.The optical spectral results demonstrated that the electron excitation temperature was 0.4-1 eV,the gas temperature was 2800-4200 K and the electron density was in the range of（5-20）×10^15 cm^-3.The mass spectrum indicated that a variety of unsaturated hydrocarbons（C2H4,C3H6,C6H6,etc.） and several highly unsaturated hydrocarbons（C4H2,C5H6,etc.） were produced in the non-thermal arc plasmas.
基金the financial support from Project 81771983, 81750110544, 81750410695, 81650110523, and 81471096 (to LXQ) by National Natural Science Foundation of China (NSFC)Project 16441909300 by Shanghai Science and Technology Commission+2 种基金Project 2017YFC0909000 by Ministry of Science and Technology of Chinasponsored by the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (TP2015015)supported by 14DZ2272400 Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition (to WC)
文摘Nutriology relies on advanced analytical tools to study the molecular compositions of food and provide key information on sample quality/safety. Small nutrients detection is challenging due to the high diversity and broad dynamic range of molecules in food samples, and a further issue is to track low abundance toxins. Herein, we developed a novel plasmonic matrix-assisted laser desorption/ionization mass spectrometry(MALDI MS)approach to detect small nutrients and toxins in complex biological emulsion samples. Silver nanoshells(SiO_2@-Ag) with optimized structures were used as matrices andachieved direct analysis of ~ 6 n L of human breast milk without any enrichment or separation. We performed identification and quantitation of small nutrients and toxins with limit-of-detection down to 0.4 pmol(for melamine) and reaction time shortened to minutes, which is superior to the conventional biochemical method currently in use. The developed approach contributes to the near-future application of MALDI MS in a broad field and personalized design of plasmonic materials for real-case bio-analysis.
基金the supports of the National Key Research and Development of BioBased Rubber(2017YFB0306900&2017YFB0306901)the National Natural Science Foundation of China(51673012)+1 种基金the Fundamental Research Funds for the Central Universities(PYBZ1828)the Beijing Technology and Business Universtiy Youth Scholoars Funds(PXM2019014213000007)。
文摘Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.
基金This work was supported by the National Natural Science Foundation of China(No.51673012)National Key Research and Development Plan Fund(No.2017YFB0306901,2016YFF0203703-03)the Beijing Technology and Business University Youth Scholar Funds(No.PXM2019_014213_000007).
文摘Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.
