Trace-Level Analysis of Hexavalent Chromium in Lake Sediment Samples Using Ion Chromatography Tandem Mass Spectrometry

The analysis of hexavalent chromium, Cr(VI), in soil and sediment samples has been predominantly carried out in materials containing elevated levels. Reliable analysis of trace-level of Cr(VI) in sediment samples remains challenging. Cr(VI) analyses with multipoint calibration and speciated isotope dilution (SID) adapted from U.S. EPA method 6800 were used to measure lower-level Cr(VI) on an ion chromatograph coupled with a tandem mass spectrometer (IC-MS/MS). Lake sediment samples were collected from various locations in Northern Ontario and Cr(VI) was extracted using both alkaline digestion and ethylene diaminetetraacetic acid (EDTA) extraction. Certified reference materials were extracted and analyzed by IC-MS/MS and UV-VIS detection. The SID-MS approach allowed for the quantification of Cr(VI) in samples with concentration levels below 0.5 μg.g-1 wet weight.

Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

An accurate and sensitive method for the simultaneous determination of gibberellic acid（GA3）, gibberellin A4（GA4） and gibberellin A7（GA7） residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry（LC-MS/MS） with electrospray ionization based stable isotope dilution analysis（SIDA）. The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance（HLB） solid phase extraction（SPE） column was tested for the capacity of the cleanup of the tomato paste in compared with C18 SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA3, GA4 and GA7 were 42.6%―75.0% in external standard method（ESM） and 91.1%―103.8% in internal standard method（ISM） respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection（2 ng/g for GA3 and GA4, 0.3 ng/g for GA7）, excellent linear dynamic ranges（5―500 ng/g for GA3 and GA4, 1―100 ng/g for GA7） and good relative standard deviation ranges（4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test）.

Fast and Sensitive Chiral Analysis of Amphetamines and Cathinones in Equine Urine and Plasma Using Liquid Chromatography Tandem Mass Spectrometry

A simple, rapid, sensitive and reproducible method for enantiomer analysis of methamphetamine, amphetamine, cathinone and methcathinone was developed and validated. The compounds were extracted from equine plasma and urine using a fast liquid-liquid extraction procedure. Only one milliliter plasma and one hundred microliter urine sample is needed for analysis. The extraction procedure had good recovery (>70%) and the matrix effect was negligible. Enantiomer differentiation and confirmation were achieved using liquid chromatography with chiral stationary phase and mass spectrometry detection. The method demonstrated excellent reproducibility with intra-day and inter-day precision of lower than 5%. The lower limits of detection for all of the compounds studied here were at low pg/mL level for both plasma and urine. This is the first report of the analysis of four chiral compounds in equine plasma and urine. Routine application was demonstrated for (S)- and (R)-enantiomer differentiation.

ANALYSIS OF VOLATILE CONSTITUENTS OF CHINESE MEDICINAL HERBS BY FLASH DISTILLATION/CAPILLARY GAS CHROMATOGRAPHY/MASS SPECTROMETRY

In present work,the volatile constituents of Curcuma longa L.,A.lancea (Thunb.) DC.,Foeniculum vulgare Mill,and Cinnamomun cassia Presl.have been analyzed by flash distillation/capillary gas chro-matography/mass spectrometry.The results are consistent with those obtained by conventional steam distillation extraction method.The optimum condition of flash distillation has been studied.The experimental results showed that this new technique proved to be a simple,rapid and efficient tool for microanalysis of volatile constituents of Chinese medicinal herbs.

Coupling a Gas Chromatography Unit to an Inductively Coupled Plasma Mass Spectrometer

Although the eminent threat of a terrorist group detonating an improvised nuclear device (IND) in an urban environment is low, it is crucial that countries develop modern nuclear forensic capabilities to expedite response in a post-detonation scenario. In particular, new instruments need to be created to shorten dissolution time, expedite chemical separation, and improve forensic analysis of the nuclear melt glass that is created during the detonation of the device. To expedite this process, an instrument was designed to thermally couple a gas chromatograph (GC) to a time-of-flight inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) In order to couple these two instruments, another instrument was designed to provide an isothermal atmosphere between the GC and TOFICPMS to expedite rapid gas separations processes. By using gas separations instead of the current wet chemistry processes, the required separation and analysis time of the melt glass significantly decreases. The new instrument would also provide a more detailed analysis of the elemental and isotopic composition of the melt glass. By completing these tasks simultaneously, this significantly decreases the required time to conduct these separations and improves the elemental and isotopic analysis.

COMPREHENSIVE TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY COUPLED WITH QUADRUPLE TIME-OF-FLIGHT MASS SPECTROMETRY FOR CHEMICAL CONSTITUENTS ANALYSIS OF TRIPTERYGIUM GLYCOSIDES TABLETS

Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constituents of two types of tripterygium glycosides tablets(TGT).The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared.C8andC18 column were used for the separation of the first

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

Gas Chromatography–Mass Spectrometry for Quantitative and Qualitative Analysis of Essential Oil from Curcuma wenyujin Rhizomes

Objectives:A rapid and sensitive gas chromatography–mass spectrometry(GC–MS)method for quantitative and qualitative analysis of essential oil from Curcuma wenyujin rhizomes was established.Methods:The essential oil of C.wenyujin rhizomes was extracted by supercritical CO2 extraction(SFE).Six main bioactive compounds(eucalyptol,β-elemene,curzerene,germacrone,curdione,and curcumol)were analyzed in selected ion monitoring mode(SIM).Results:Curzerene is not originally present in C.wenyujin rhizomes,but is a product of the transformation of furanodiene at high temperature.The six target components demonstrated good linearity(R2>0.9979)over a relatively wide concentration range.The interday and intraday variations had relative standard deviation values less than 5%and the average recovery ranged from 96.95%to 100.04%.The limit of quantitation ranged from 0.032 to 0.235μg/mL.The developed method was successfully used to analyze the six compounds in 17 samples collected from different origins.Significant variation was observed for the concentrations of the six compounds.In addition,51 constituents were identified in C.wenyujin rhizome essential oil,consisting of 87.66%of the total essential oil,including curdione,curzerene,dehydrocurdione,germacrone,1,4-bis(2-benzimidazoyl)benzene,neocurdione,curcumenone,andβ-elemene.Conclusions:The proposed method will be useful in the quality control of C.wenyujin rhizome essential oil production.

Development of Analyses of Biological Steroids Using Chromatography——Special Reference to Vitamin D Compounds and Neurosteroids

Steroids comprise a large group of natural substances that must frequently be monitored in various biological materials. Due to the metabolic versatility of steroid molecules, extremely complex mixtures are often encountered, necessitating the use of a chromatographic procedure prior to measurement. In this article we present our work, that is, the development of analyses of biological steroids (especially vitamin D compounds and neurosteroids) using gas chromatography/mass spectrometry, high-performance liquid chromatography (including inclusion chromatography using cyclodextrin) and liquid chromatography/mass spectrometry.

Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction（SPE） for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry （UPLC/MS/MS） and multivariate analysis.Several adsorbing materials of SPE（C18,NH2,SAX and OASIS） were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols in tobacco samples after purification.All analytes were separated and determined in 2min.The limit of detection was 0.05 ng/mL.Cluster analysis（CA） and principal component analysis（PCA） were used for the analysis of 4 varieties（flue-cured tobacco,oriental tobacco,sun-cured tobacco and burley） in order to interpret the effect of planting and machining process on the concentration of polyphenols.The different types of tobacco samples could be easily clustered by CA.PCA on the chemical composition of tobacco resulted in two principal components（PCs） that take 84.2% of the total variance.The PCA and CA indicate that the polyphenols can be used for distinguishing tobacco types.

Determination of Periplocymarin in Human Blood and Urine by High-Performance Liquid Chromatography-Mass Spectrometry

A simple,rapid and sensitive liquid chromatography with tandem mass spectrometry method for the determination of periplocymarin in human blood and urine was developed.The digoxin‑d3 was used as an internal standard.Periplocymarin and digoxin‑d3(IS)were processed with ethyl acetate by liquid–liquid extraction.The chromatographic separation was performed on a Shim‑pack XR‑ODSIII C18 column with a 7 min gradient elution using methanol‑ammonium formate(5 mmol/L)as mobile phase at a flow rate of 0.3 mL/min(65:35,v/v).The detection was performed on a triple quadrupole tandem mass spectrometer using positive‑ion mode electrospray ionization in selected reaction monitoring mode.The periplocymarin was well separated from the internal standard.Two calibration curves were linear within the concentration range 0.01–1µg/mL.The limit of detection and quantification of blood and urine samples were both estimated at 0.005 and 0.01µg/mL.The interday and intraday precisions,accuracy,and recovery were assessed to verify this method.The results showed that the method was suitable for the determination of periplocymarin in forensic toxicological analysis and clinical diagnosis.

Qualitative and Quantitative Analysis of Five Bioactive Flavonoids in <i>Salix bordensis</i>Turcz. by HPLC-DAD and HPLC-ESI-MS

The qualitative characterization and quantitative analysis of five bioactive flavonoids in Salix bordensis Turcz. were achieved via reversed-phase high-performance liquid chromatography coupled with diode array detection and tandem mass spectrometry, by using an Agilent ZORBAX SB-C18 HPLC column with a gradient elution of 0.3% (v/v) formic acid in water and methanol as the mobile phase. The compounds in the mixture were clearly identified by comparing their HPLC-DAD ultraviolet spectra, retention times, and MS data with those of corresponding reference compounds. All calibration curves showed good linearity (r2 > 0.9998) within the test ranges. The LOD, LOQ, specificity, precision, and accuracy for the method were validated. The results demonstrated that this analytical approach is ideal for the determination of bioactive compounds, such as flavonoids, and that it constructed a basis for the comprehensive evaluation of the quality of Salix bordensis Turcz.

Integrated metabolomic profiling for analysis of antilipidemic effects of Polygonatum kingianum extract on dyslipidemia in rats

AIM To identify the effects and mechanism of action of Polygonatum kingianum(P. kingianum) on dyslipidemia in rats using an integrated untargeted metabolomic method.METHODS A rat model of dyslipidemia was induced with a high-fat diet(HFD) and rats were given P. kingianum [4 g/(kg·d)] intragastrically for 14 wk. Changes in serum and hepatic lipid parameters were evaluated. Metabolites in serum, urine and liver samples were profiled using ultra-highperformance liquid chromatography/mass spectrometry followed by multivariate statistical analysis to identify potential biomarkers and metabolic pathways.RESULTS P. kingianum significantly inhibited the HFD-induced increase in total cholesterol and triglyceride in the liver and serum. P. kingianum also significantly regulated metabolites in the analyzed samples toward normal status. Nineteen, twenty-four and thirty-eight potential biomarkers were identified in serum, urine and liver samples, respectively. These biomarkers involved biosynthesis of phenylalanine, tyrosine, tryptophan, valine, leucine and isoleucine, along with metabolism of tryptophan, tyrosine, phenylalanine, starch, sucrose, glycerophospholipid, arachidonic acid, linoleic acid, nicotinate, nicotinamide and sphingolipid.CONCLUSION P. kingianum alleviates HFD-induced dyslipidemia by regulating many endogenous metabolites in serum, urine and liver samples. Collectively, our findings suggest that P. kingianum may be a promising lipid regulator to treat dyslipidemia and associated diseases.

Discrimination of aqueous and vinegary extracts of Shixiao San using metabolomics coupled with multivariate data analysis and evaluation of antihyperlipidemic effect

A novel study using LCeMS(Liquid chromatography tandem mass spectrometry)coupled with multivariate data analysis and bioactivity evaluation was established for discrimination of aqueous extract and vinegar extract of Shixiao San.Batches of these two kinds of samples were subjected to analysis,and the datasets of sample codes,tR-m/z pairs and ion intensities were processed with principal component analysis(PCA).The result of score plot showed a clear classification of the aqueous and vinegar groups.And the chemical markers having great contributions to the differentiation were screened out on the loading plot.The identities of the chemical markers were performed by comparing the mass fragments and retention times with those of reference compounds and/or the known compounds published in the literatures.Based on the proposed strategy,quercetin-3-Oneohesperidoside,isorhamnetin-3-O-neohespeeridoside,kaempferol-3-O-neohesperidoside,isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-(2G-a-l-rhamnosyl)-rutinoside were explored as representative markers in distinguishing the vinegar extract from the aqueous extract.The anti-hyperlipidemic activities of two processed extracts of Shixiao San were examined on serum levels of lipids,lipoprotein and blood antioxidant enzymes in a rat hyperlipidemia model,and the vinegary extract,exerting strong lipid-lowering and antioxidative effects,was superior to the aqueous extract.Therefore,boiling with vinegary was predicted as the greatest processing procedure for anti-hyperlipidemic effect of Shixiao San.Furthermore,combining the changes in the metabolic profiling and bioactivity evaluation,the five representative markers may be related to the observed antihyperlipidemic effect.

Determination of selected semi-volatile organic compounds in water using automated online solid-phase extraction with large-volume injection/gas chromatography/mass spectrometry

A rapid,sensitive,and cost-effective analyticalmethod was developed for the analysis of selected semivolatileorganic compounds in water.The method used anautomated online solid-phase extraction technique coupledwith programmed-temperature vaporization large-volumeinjection gas chromatography/mass spectrometry.Thewater samples were extracted by using a fully automatedmobile rack system based on x-y-z robotic techniquesusing syringes and disposable 96-well extraction plates.The method was validated for the analysis of 30 semivolatileanalytes in drinking water,groundwater,andsurface water.For a sample volume of 10 mL,the linearcalibrations ranged from 0.01 or 0.05 to 2.5μg·L^(-1),and themethod detection limits were less than 0.1μg·L^(-1).For thereagent water samples fortified at 1.0μg·L^(-1)and2.0μg·L^(-1),the obtained mean absolute recoveries were70%-130%with relative standard deviations of less than20%for most analytes.For the drinking water,groundwater,and surface water samples fortified at 1.0μg·L^(-1),theobtained mean absolute recoveries were 50%-130%withrelative standard deviations of less than 20%for mostanalytes.The new method demonstrated three advantages:1)no manipulation except the fortification of surrogatestandards prior to extraction;2)significant cost reductionassociated with sample collection,shipping,storage,andpreparation;and 3)reduced exposure to hazardous solventsand other chemicals.As a result,this new automatedmethod can be used as an effective approach for screeningand/or compliance monitoring of selected semi-volatileorganic compounds in water.

The analysis of volatile flavor components of Jin Xiang garlic and Tai’an garlic

The volatile flavor compounds of Jin Xiang garlic and Tai’an garlic in chemical composition were detected and analyzed and the contents of them were compared and determinated. The volatile constituents of Jin Xiang garlic and Tai’an garlic were compared and analyzed by automatic static headspace and gas chromatography-mass spectrometry. Qualitative analysis of samples was made through the analysis of gas chromatography-mass spectrometry and NIST mass spectral library computer retrieval, and quantitative analysis was made by using area normalization method. The analysis results show that the slight difference of the volatile flavor compounds was detected in different places of origin garlic and Jin Xiang garlic was detected more total sulfur-containing compounds than Tai’an garlic. Meanwhile, the contents of sulfur compounds of the fresh garlic were more than the stored garlic and there were significant differences between them. The tests results indicated that flavor substances’ types were slightly different between Jin Xiang garlic and Tai’an garlic, and regional differences cannot affect the garlic flavor substances type. Jin Xiang garlic has more obvious flavor substances than Tai’an garlic which play a decisive role in the garlic flavor, such as 1,3-dithiane, and allyl trisulfide and allyl disulfide and diallyl tetrasulphide. The result of this research indicates that Automatic static headspace and gas chromatography-mass spectrometry is a fast, easy, efficient and accurate method to analyze and identify the volatile flavor components of garlic.

Triacontyl modified silica gel as a sorbent for the preconcentration of polycyclic aromatic hydrocarbons in aqueous samples prior to gas chromatographic-mass spectrometry determination

Triacontyl modified silica gel as a sorbent coupled with gas chromatography-mass spectrometry(GC-MS) was developed to determine EPA prior 16 polycyclic aromatic hydrocarbons(PAHs) in water samples.Various parameters of solid-phase extraction such as organic modifier solvent,eluent,sample flow rate and volume were optimized.The developed method was found to yield a linear calibration curve in the concentration range of 0.05-8μg/L with respect to naphthalene,acenaphthylene,acenaphthene and 0.01-8μg/L for dibenz[a,h]anthracene and 0.05-14μg/L for fluorene,phenanthrene,anthracene and 0.01-14μg/L for the rest of analytes.Furthermore,the good accuracy and repeatability of the method made sure the requirements for achieving reliable analysis of PAHs in the environmental water samples,and the recoveries of optimal method were in the range of 80-120%except to higher volatility PAHs.C_(30)-bonded silica was proved to be an efficient sorbent for extraction of high molecular weight PAHs.

Relationship between cardiotonic activity of Fuzi(Radix Aconiti Lateralis Preparata)and its fingerprint determined by liquid chromatography-mass spectrometry

OBJECTIVE:To investigate the relationship between the cardiotonic activity of Fuzi(Radix Aconiti Lateralis Preparata,RALP)and its fingerprint determined by liquid chromatography-mass spectrometry(LC-MS).METHODS:First,the fingerprints of six processed products of RALP were established by high performance liquid chromatography quadrupole time-of-flight mass spectrometry(HPLC-Q-TOF-MS)followed by analysis of the principal component of the relative peak area of its common peaks.Next,the scores of the first five principal components were used as input for an artificial neural network(ANN).Additionally,the therapeutic effect of RALP was assessed by measuring the hemodynamic indexes of heart failure model rats.Subsequently,fluorescence semi-quantitative polymerase chain reaction and an enzyme-linked immunosorbent assay kit were used to determine the effects of RALP-processed products on the serum levels of noradrenaline(NA),angiotensin-Ⅰ(Ang-Ⅰ),and the expression ofβ-norepinephrine receptor m RNA(β-NRm)in the rat cardiac tissues.P<0.05 was used as the output of the ANN.Finally,a network was constructed to display the relationship between the LC-MS fingerprints and the cardiotonic activity of the RALP-processed products.RESULTS:Several types of RALPs can improve diastolic function,systolic function and heart rate.On the basis of the findings from the principal component analysis(PCA)of 16 common peaks of fingerprints of six RALP-processed products,it was revealed that the first five principal components may include 100%of the information of the original data.As observed from the multilayer perceptron neural network analysis,principal component 4 presented with the strongest effects on serum levels of NA and Ang-Ⅰin rats,while principal component1 exerted the greatest effect onβ-NRm expression in cardiac tissue.CONCLUSION:The key findings obtained from this study indicated that the network constructed by the PCA-ANN may predict pharmacodynamic effects of the main ingredients of Traditional Chinese Medicine(TCM).This method may serve as a new approach to identify the relationship between LC-MS fingerprints and the pharmacodynamic effects of TCM ingredients.

不同产地花椒中多酚类物质的鉴定与差异性分析

以不同产地大红袍花椒为研究对象,通过高效液相串联飞行时间质谱技术对花椒中多酚类物质进行定性和定量分析,并采用主成分分析法对各产地花椒进行综合评价。结果表明:在8个产地花椒中共鉴定出多酚类物质35种,其中酚酸类物质10种、黄酮类物质20种、香豆素类物质4种和酚醛类物质1种;17种多酚定量结果表明,绿原酸、槲皮苷和金丝桃苷是花椒中含量最高的3种多酚类化合物;对8个产地花椒中存在相关性的12种酚类物质做主成分分析并构建主成分得分表达式,结果显示,陕西安康大红袍花椒综合得分最高。综上表明,花椒中多酚类物质分布存在显著差异,并且以安康样品为最佳。

基于电子鼻和气质联用分析萌芽大蒜挥发性物质差异

为探究萌芽期大蒜挥发性物质的差异,采用电子鼻、捕集阱顶空-气质联用仪(Trap head space-gas chromatography-mass spectrometry,HS-Trap-GC-MS)结合正交偏最小二乘法判别分析(Orthogonal partial least squares discriminant analysis,OPLS-DA)、香气活度值、差异性热图、相关性分析分析大蒜萌芽在0、24、48、72、96 h挥发性物质的差异。电子鼻结合OPLS-DA建立预测模型其预测能力达96.00%。GC-MS分析表明:含硫化合物是不同萌芽期大蒜的主要共有挥发性物质,含硫化合物的相对含量随萌芽时间的延长而呈递减趋势,而种类呈现出递增趋势;二烯丙基二硫醚是样品在萌芽过程中含量降低最多的物质。二烯丙基四硫醚、烯丙硫醇是样品共有关键化合物。差异性热图分析显示:除共有物质含量差异外,硫化丙烯、己醛、叠氮二羧酸二叔丁酯、丙烯醇、6-甲基-2-庚炔、5-甲基噻二唑、2-亚乙基-1,3-二硫烷、2-丙-2-炔基磺酰基丙烷、2,5-二甲基噻吩、2,5-二甲基呋喃、1-戊烯-3-醇、1,3-二噻烷的缺失进一步加大了未萌芽和萌芽大蒜气味的差异。萌芽大蒜主要共有挥发性物质的种类随萌芽时间的延长呈现递增趋势。大蒜主要挥发性物质与电子鼻大多数传感器存在显著相关性。大蒜的气味强度会随萌芽时间的延长而逐步减弱。