Screening for Plant Toxins in Honey and Herbal Beverage by Ultrahigh-Performance Liquid Chromatography-Ion Mobility-Quadrupole Time of Flight Mass Spectrometry

The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time of flight mass spectrometry (IM-QTOF MS) in positive ion mode. A database of 308 plant toxins including retention time, collision cross-section (CCS) and its fragment ions was established. Honey dissolved in water or herbal beverage was extracted by acetonitrile and purified with PSA sorbent, and then acquired by ultrahigh-performance liquid chromatography IM-QTOFMS. The acquired data were processed by comparing with the database we established to confirm the target compounds. The average recoveries for samples at two levels ranged from 60.6% - 120.1%, with relative standard deviation (n = 6) less than 25%. The limit of quantitation for plant toxins ranged from 1 - 20 μg/kg. The developed screening method was used in determination of honey, herbal beverage and honey flavored tea beverage samples. The results showed that berberine was detected in one honey with 1 μg/kg and caffeine was present in some beverages with the concentration from 200 and 5500 μg/kg. This method could meet the requirement for rapid screening of plant toxins in honey and herbal beverage. It can be used for the quality control of honey and herbal beverage in enterprises or quality inspection departments. It also can be used in the rapid screening of food poisoning.

Analyzing crude oils from the Junggar Basin(NW China) using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS)

As a new technology of analyzing crude oils, comprehensive two-dimensional gas chromatography cou- pled with time-of-flight mass spectrometry （GCxGC- TOFMS） has received much research attention. Here we present a case study in the Junggar Basin of NW China. Results show that the hydrocarbons, including saturates and aromatics, were all well-separated without large co- elution, which cannot be realized by conventional one-dimensional GC-MS. The GC×GC technique is especially effective for analyzing aromatics and low-to-middle- molecular-weight hydrocarbons, such as diamondoids. The geochemical characteristics of crude oils in the study area were investigated through geochemical parameters extracted by GC×GC-TOFMS, improving upon the understanding obtained by GC-MS. Thus, the work here represents a new successful application of GC×GC- TOFMS, showing its broad usefulness in petroleum geochemistry.

Two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry for detection of protein expression profiles in the hippocampus following closed brain injury

Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modification. Therefore, it is necessary to quantitatively analyze the gene expression profile using proteomic techniques. In the present study, we established a rat model of closed brain injury using Marmarou＇s weight-drop device, and investigated hippocampal differential protein expression using two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry. A total of 364 protein peaks were detected on weak cation exchange-2 protein chips, including 37 differential protein peaks. 345 protein peaks were detected on immobilized metal affinity capture arrays-Cu, including 12 differential protein peaks Further examination of these differential proteins revealed that glucose-regulated protein and proteasome subunit alpha type 3 expression were significantly upregulated post-injury. These results indicate that brain injury can alter protein expression in the hippocampus, and that glucose-regulated protein and proteasome subunit alpha type 3 are closely associated with the occurrence and development of traumatic brain injury.

CO₂Absorption Solvent Degradation Compound Identification Using Liquid Chromatography-Mass Spectrometry Quadrapole-Time of Flight (LCMSQTOF)

The degradation of the alkanolamine solvent used in the removal of acid gases from natural gas streams due to exposure to contaminants, thermal degradation and presence of oxygen or oxygen containing compounds will change the solvent properties, such as heat transfer coefficient, diffusion coefficient, and mass transfer coefficient of the solvent. Therefore, characterization and quantification of amine degradation product becomes one of the important analyses to determine alkanolamine solvent’s health. In order to identify degradation products of alkanolamine solvent, analytical strategies by using mass spectrometry (MS) as detector have been studied extensively. In this work, due to the low concentration of the amine degradation product, a method was developed for identification of alkanolamine degradation products using LCMS-QTOF technique. A strategy for identification of trace degradation products has been identified. Six (6) alkanolamine degradation products had been identified by using LCMS-QTOF targeted analysis in the blended alkanolamine solvent used in natural gas processing plant. Another fifteen (15) molecular formulas having similarity in chemical structure to alkanolamine degradation products were identified using untargeted analysis strategy, as possible compounds related to degradation products. Using LCMS-QTOF via targeted and untargeted analysis strategy, without tedious column separation and reference standard, enables laboratory to provide a quick and indicative information for alkanolamine solvent’s organic degradation compounds identification in CO2 adsorption, within reasonable analysis time.

A novel sample preparation method of matrix-assisted laser desorption/ionization time of flight mass spectrometry for polystyrene

A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved. The mechanism was also analyzed.

Studies on Fragmentation Regularity of 5-Methoxycarbonyl- 4-substituted-6-methyl-3,4-dihydropyrimidin-2(1H)-ones by Time-of-flight Mass Spectrometry

The electron impact time-of-flight(TOF) mass spectra of the title compounds were studied to establish their fragmentation processes. With the high resolution of the TOF instrument, the exact mass for each fragment was determined. These data were used to infer the molecular formulas and the elemental compositions for all the molecular ions and fragments through software interpretation. By further applying the fragmentation regularity, the majority of ions were fully assigned. The main fragmentation pathways of the title compounds include the formation of molecular ions by the loss of R 1 groups in the 4-position and the ester groups in the 5-position. The formed ion can be further fragmented by the elimination of MeOH.

The Development of Time-of-flight Mass Spectrometry( TOF-MS) and Its Applications in Screening Food Hazard Factors

The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide mass range,high resolution and mass measurement accuracy,high sensitivity and high analysis speed.In this paper,research progresses of TOF-MS on the detection of food additives,food contaminants and residues,illegal additives,pesticide residues,veterinary drug residues and mycotoxin were reviewed,and its probable approaching applications were prospected.

MicrobMatcher: a microbial comparison software based on matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry

Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention.

Identification of serum biomarkers for diagnosing stage Ⅰ lung adenocarcinoma by MALDI-TOF mass spectrometry

Objective To identify specific biomarkers that could improve early diagnosis of lung adenocarcinoma using matrix-assisted laser desorption/ionization (MALDI) technology. Methods Serum samples were isolated from 17 patients with stage Ⅰ lung adenocarcinoma and 17 age-and sex-matched healthy controls,and the serum proteomic profiles were obtained by matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. Results Compared with healthy control group,two highly expressed potential biomarkers were identified with the relative molecular weights of 6 631.64 Da and 4 964.21 Da. The two best novel protein peaks were automatically chosen for the system training and the development of the constructed model. The constructed model was then used to test an independent set of masked serum samples from 15 lung adenocarcinoma patients and 22 healthy individuals. The analysis yielded a sensitivity of 93.3%,and a specificity of 95.5%. Conclusion These results suggest that MALDI-TOF-MS ProteinChip technology is a quick,convenient,and high-output analyzing method that is capable of selecting several relatively potential biomarkers from the serum of lung adenocarcinoma patients and may have a clinical value in the future,and will provide clues to identifying new serologic biomarkers of lung adenocarcinoma.

基于UHPLC-QTOFMS的黄芩汤化学成分和大鼠入血成分分析

建立了一种超高效液相色谱-四极杆飞行时间质谱(UHPLC-QTOF MS)联用鉴定黄芩汤化学成分及大鼠灌胃给药后入血成分的方法。采用ACQUITY UPLC XBridge BEH C_(18)色谱柱(2.1 mm×100 mm,2.5µm),以0.1%甲酸水和0.1%甲酸乙腈为流动相梯度洗脱;使用电喷雾离子源正负离子模式采集碎片信息。依据质谱裂解规律,结合对照品、文库比对分析,初步鉴定了黄芩汤中68种化学成分和35种入血成分,并讨论了黄芩素、黄芩苷、芍药苷、甘草苷等的治疗潜力。该方法高效、稳定、灵敏,可为黄芩汤的药效物质基础研究提供参考,也可用于其他复方的成分分析,有助于提升传统中药中小分子药物发现的效率。

Establishment and Preliminary Application of Two dimensional Electrophoresis and Mass Spectrometry in Ovary Study

Objective To apply two-dimensional electrophoresis and mass spectrometry in the ovary proteome researchMethods Protein extractions from mouse ovaries were run in IPGphor isoelectric focus system with 11 cm and 24 cm IPG strips respectively (pH 3～10, 0.3 mm thick), then the protein spots were identified by mass spectrometry.Results The ovary protein exactions separated by two-dimensional electrophoresis have got high resolution, and identifing protein by mass spectrometry was highly efficient and facilitly. These two techniques should facilitate further investigation of female reproduction proteome research.Conclusion These two rapid high resolutions and efficient techniques have a variety of applications foreground in female reproduction proteome pattern research.

Improved preparation and identification of aristolochic acid-DNA adducts by solid-phase extraction with liquid chromatography-tandem mass spectrometry

Aristolochic acid （AA） is a known nephrotoxin and potential carcinogen, which can form covalent DNA adducts after metabolic activation in vivo and in vitro. A simple method for preparation and characterization of aristolochic acid-DNA adducts was developed. Four AA-adducts were synthesized by a direct reaction of AAI/AAII with 2′-deoxynucleosides. The reaction mixture was first cleaned-up and pre-concentrated using solid phase extraction （SPE）, and further purified by a reversed-phase high performance liquid chromatography （HPLC）. By the application of developed SPE procedure, matrices and byproducts in reaction mixture could be greatly reduced and adducts of high purity （more than 94% as indicated by HPLC） were obtained. The purified AA-DNA adducts were identified and characterized with liquid-electrospray ionization-quadrupole-time of flight-mass spectrometry （LC-ESI-Q-TOF-MS/MS） and LC-Diode array detector-fluorescence （LC-DAD-FL） analysis. This work provides a robust tool for possible large-scale preparation of AA-DNA adduct standards, which can promote the further studies on carcinogenic and mutagenic mechanism of aristolochic acids.

Characterization of 4-Aryl-5-ethoxycarbonyl-6-methyl-3,4-dihydro-pyrimidin-2(1H)-thiones by EI-TOF Mass Spectrometry

The electron impact （EI） time-of-flight mass spectra （TOFMS） of the title compounds （ thioxo-Biginelli compounds） were studied to establish their fragmentation pathways. With a TOF instrument of high resolution, the exact mass for each fragment was determined. These data were used to infer the molecular formulas and the ionic elemental compositions for all the compounds through interpretation by software. By further applying chemical intuition, majority of the fragmentation ions were fully assigned. All the compounds give strong signals（ average 76% ） for their molecular ions in the El spectra. Two kinds of characteristic fragmentation pathways from the molecular ion were observed. One is related to the loss of the ester group, forming a resonance stabilized ion with a moderate abundance（ average 40% ）. The other concerns the loss of the aromatic-ring radical, forming another resonance stabilized ion at m/z 199 with a high abundance（ average 79% ）, from which further important fragmentations including the formation of an ion at m/z 171 （average 24% ） by the loss of C2H2 （via the McLafferty rearrangement）, and an ion at m/z 153（ average 10% ） by the elimination of a water molecule preceed. In addition, ion [ M - Et ]^＋ with a high abundance（average 62% ） is a characteristic for the Biginelli compounds with an ethoxycarbonyl group. Differences and similarities among the fragmentations observed from the EI-TOFMS of oxo-Biginelli compounds are discussed.

Screening and Identifying of Nephrotoxic Compounds in Lithospermum erythrorhizon Using Live-cell Fluorescence Imaging and Liquid Chromatography Coupled with Tandem Mass Spectrometry

In order to identify the potential nephrotoxic compounds in traditional Chinese medicine Lithospermum erythrorhizon,it was separated into serial fractions according to their polarities.An in vitro method was utilized to determine the nephrotoxicity of these fractions with the help of fluorescence image analysis.As a result,the primary fraction A05 and its secondary fractions C06 ＂C09 and C12 ＂C14 were found to have significant toxicity to LLC-PK1 cell line,as determined by the survive rate less than 20% after they were treated with these fractions.These potential nephrotoxic fractions were further analyzed by multistage and high resolution mass spectrometry.The main compounds in these fractions were tentatively identified to be acetylshikonin,isobutyrylshikonin,β,β＇-dimethyla-cryloylshikonin,and isovalerylshikonin,which may bring nephrotoxicity.

GLOBAL ANALYSIS OF THE METABOLITES OF CURCUMIN IN RATS BY ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY COUPLED WITH QUADRUPOLE TIME OF-FLIGHT TANDEM MASS SPECTROMETRY

Curcumin,a safe natural yellow pigment with a wide range of pharmacological activities,is used both in herbal drugs and as a food coloring agents.Studies have shown that curcumin would suffer from extensive metabolism in vivoand the predominant metabolic pathways are reduction and conjugation.In order to comprehensively study the metabolism and enrich the metabolic profile of cxurcumin in vivo,we carried out this research.A systematic method with highly sensitive UPLC-Q/TOF-MS was established to analyze different biological samples of rats after

Identification of petroleum aromatic fraction by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS) is commercially available in the 1990s,with the characteristics of large peak capacity,high resolution,high sensitivity,etc.However,its application to the petroleum and geological analyses is just emerging in China and overseas.In this research,the analytical method for petroleum aromatic fraction using GC×GC-TOFMS is set up,via the choice of the column system and optimization of setting parameters,such as temperature programming,modulation time,hot pulse time,flow rate of carrier gas,data acquisition rate and data processing.The results indicate that different polar compounds of aromatic fraction distribute as bands on structured GC×GC chromatogram.Within each band,homologous compounds appear as a roof-tile structure based on the number of substituent residues.The aromatic compounds are identified and characterized according to the GC×GC chromatogram and mass spectra.According to the polarity and the number of rings,aromatic compounds are spatially present on one chromatogram,which directly reflects the distribution characteristics of complex compounds of aromatic hydrocarbons.In addition,quantitative analysis is favored as some overlapped peaks on traditional GC-MS chromatogram have been separated completely on GC×GC.Some heterocyclic atom aromatic compounds at trace level can be clearly identified using this method,for polarity differences from other interfered aromatic compounds.The development of this method and chromatogram recognition offer petroleum geologists a practical example for the application performance of GC×GC-TOFMS.

Qualitative Analysis of A Sulfur-fumigated Chinese Herbal Medicine by Comprehensive Two-Dimensional Gas Chromatography and High-Resolution Time of Flight MassSpectrometry Using Colorized Fuzzy Difference Data Processing

To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis. A comprehensive two-dimensional gas chromatography (GCxGC) and high-resolution time-of-flight mass spectrometry (HR-TOF/MS) with colorized fuzzy difference (CFD) method was used to investigate the effect of sulfur-fumigation on the volatile components from Radix Angelicae Sinensis. Twenty-five compounds that were found in sun-dried samples disappeared in sulfur-fumigated samples. Seventeen volatile components including two sulfur-containing compounds were newly generated for the first time in volatile oils of sulfur-fumigated Radix Angelicae Sinensis. The strategy can be successfully applied to rapidly and holistically discriminate sun-dried and sulfur-fumigated Radix Angelicae Sinensis. GCxGC-HR-TOF/MS based CFD is a powerful and feasible approach for the global quality evaluation of Radix Angelicae Sinensis as well as other herbal medicines.

Exact Mass Measurements for α-Allenic Alcohol by Atmospheric Pressure Chemical Ionization/Time-of-flight Mass Spectrometry

The atmospheric pressure chemical ionization/time of flight mass spectrometry (APCI/TOF MS) was applied to determine the mass of five α allenic alcohols via their protonated molecular ions using positive ion mode. Polyethylene glycol (PEG) was used as the internal reference. All results were obtained under the resolution of about 5000 FWHM (full width at the half maximum). Solvent effects were studied and the satisfied results were obtained in acetonitrile. Compared with the theoretical values, all absolute errors were less than 1.0 mmu. The effects of nozzle potential, push pulse potential, pull pulse potential, pull bias potential and acquisition rate on exact mass determination were also discussed. APCI/TOF MS is proven to be a very sensitive analytical technique and an alternative ionization mode in analyzing thermally labile compounds with relatively weak polarity, such as α allenic alcohol.