Extraction of essential oil from shaddock peel and analysis of its components by gas chromatography-mass spectrometry

Essential oil, with more than thirty kinds of compounds separated and identified by gas chromatography-mass spectrometry, was extracted from Shatian shaddock peel and Sweet shaddock peel by squeeze-steam distillation and direct steam distillation method. Among their composition, the main components are terpene compounds, which account for 93.926% (mass fraction, the same below) and 85.843% of essential oils extracted from Shatian shaddock peel and Sweet shaddock peel, respectively. Although nootkatone is the major contributor of shaddock characteristic scent, and its contents are 1.069% and 1.749% of essential oils from Sweet shaddock peel and Shatian shaddock peel, respectively. The results show that squeeze-steam distillation gives higher yield and good quality of essential oil and the compositions of essential oils from two kinds of shaddock peels are different, but the main contributors of the shaddock scent are the same.

Pyrolysis-Gas Chromatography/Mass Spectrometry for Microstructure and Pyrolysis Pathway of Polyester-Polyether Multiblock Copolymer

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.

Determination of 8 Diuretics and Probenecid in Human Urine by Gas Chromatography-Mass Spectrometry: Confirmation Procedure

A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.

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.

Headspace Solid-Phase Micro-Extraction Gas Chromatography/Mass Spectrometry(HS-SPME-GC/MS)-Based Untargeted Metabolomics Analysis for Comparing the Volatile Components from 12 Panax Herbal Medicines

Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.

Occurrence of <i>N</i>-Acyl Homoserine Lactones in Extracts of Bacterial Strain of <i>Pseudomonas aeruginosa</i>and in Sputum Sample Evaluated by Gas Chromatography–Mass Spectrometry

This study presents a fast, accurate and sensitive technique using gas chromatography-mass spectrometry (GC-MS) for the identification and quantification of N-acyl homoserine lactones (AHLs) in the extracts of bacterial strain of Pseudomonas aeruginosa and sputum sample of a cystic fibrosis patient. This method involves direct separation and determination of AHLs by using GC-MS as simultaneous separation and characterization of AHLs were possible without any prior derivatiza-tion. Electron ionization resulted in a common fragmentation pattern with the most common fragment ion at m/z 143 and other minor peaks at 73, 57 and 43. The limit of detection for N-butanoyl, N-hexanoyl, N-octanoyl, N-decanoyl, N-dodecanoyl and N-tetradecanoyl homoserine lactones was 2.14, 3.59, 2.71, 2.10, 2.45 and 2.34 μg/L, respectively. The presence of AHLs in the culture of P. aeruginosa strain and spu-tum of a cystic fibrosis patient was achieved in selected ion monitoring (SIM) mode by using the prominent fragment at m/z 143.

Structure Elucidation of a New Toxin from the Mushroom Cortinarius rubellus Using Gas Chromatography-Mass Spectrometry (GC-MS)

Cortinarius orellanus (Fries) and C. rubellus (Cooke),which were formerly also known as C. speciosissimus, are poisonous mushrooms containing the toxin orellanine and several degradation products of orellanine,includingorelline and orellinine. Mass intoxication by poisonous mushrooms was observed in Poland in 1952-1957 [1]. In 1957, the cause of these outbreaks was described by Grzymala as poisoning by a member of the Cortinarius family. The toxin orellanine was first isolated from C. orellanusby Grzymala in 1962;the chemical structure of orellanine was later determined to be 3,3',4,4'-tetrahydroxy-2,2'-bipyridine-N,N'-dioxide. Poisoning with C. orellanus and C. rubellus has a very specific character. The first symptoms of intoxication usually do not appear until 2-3 days after ingestion, but in some cases intoxication appears after three weeks. The target organ for the toxin is the kidney. Histologically, it is easy to record the specific damage. The presence of degradation products of orellanine in kidney can be confirmed chromatographically, suggesting that the cause of poisoning is orellanine. However, the presence of orellanine in the blood of intoxicated persons has not been directly detected. A specific model was developed by Brondz et al. for the detection of orellanine, orelline, and orellininein animal stomach fluids [2-4]. The hypothesis that the fungal toxin orellanine as a diglucoside can be transported from the digestive system by the blood to the kidney could not be supported. The toxin orellanine as a diglucoside is very unstable in an aqueous acidic environment.[i1]?However, in the present study, it was possible to record an additional substance in animal stomach fluids using GC-MSafter ingestion ofC. rubellus. This substance, which has been namedrubelline, is part of a toxic mixture inC. orellanusandC. rubellusand is closely related to orellanine. The structure of rubelline is more suitable than orellanine for absorptionfromthe digestive tract and for transport in the blood. The presented hypothesis is that rubellineis absorbed in the digestive tract and transportedin the blood to the kidney, where it is biotransformed to orellanine and accumulatedto toxic levels. The process of biotransformationis in itself also damaging for the kidney and liver.[i2]?GC-MS instrumentation enables the separation of substances in biological samples and in the extract fromC. rubellus. The GC-MS with SMB technique was used to record the mass ion and to record a detailed fragmentation picture.

The Detection of THCA Using 2-Dimensional Gas Chromatography-Tandem Mass Spectrometry in Human Fingernail Clippings: Method Validation and Comparison with Head Hair

Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues including workplace, court ordered, and substance abuse treatment monitoring. After the presentation of a fully validated 2-dimensional gas chromatography-tandem mass spectrometry method for the detection of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA), the chief metabolite of the main psychoactive compound in marijuana, Δ9-tetrahydrocannabinol (THC), we evaluated the usefulness of fingernail clippings as an alternative specimen type to hair by the analysis of a set of 60 matched pairs of head hair and fingernail clippings. The limit of detection was 10 fg/mg, the limit of quantitation was 20 fg/mg, and the assay was linear from 20 fg/mg to 500 fg/mg. The intra- and inter-assay imprecision and bias studies at 4 different concentrations (50, 100, 500, and 1000 fg/mg) were acceptable where all % Target observations were within 16% of their expected concentrations and all %CV calculations were less than 13.5%. THCA was detectable in more fingernail specimens (53.3%) than hair specimens (46.7%) and the mean concentrations in nails were on average 4.9 times higher than in hair (1813 fg/mg and 364 fg/mg, respectively). The THCA concentrations in hair and nail were strongly associated (r = 0.974, P < 0.01, n = 60) and the association was significant. The study demonstrated that fingernail clippings are a suitable alternative specimen type to hair to monitor for marijuana use and abuse.

Metabolomics of gastric cancer metastasis detected by gas chromatography and mass spectrometry

AIM:To elucidate the underlying mechanisms of metastasis and to identify the metabolomic markers of gastric cancer metastasis.METHODS:Gastric tumors from metastatic and nonmetastatic groups were used in this study.Metabolites and different metabolic patterns were analyzed by gas chromatography,mass spectrometry and principal components analysis (PCA),respectively.Differentiation performance was validated by the area under the curve (AUC) of receiver operating characteristic curves.RESULTS:Twenty-nine metabolites were differentially expressed in animal models of human gastric cancer.Of the 29 metabolites,20 were up-regulated and 9 were down-regulated in metastasis group compared to non-metastasis group.PCA models from the metabolite profiles could differentiate the metastatic from the nonmetastatic specimens with an AUC value of 1.0.These metabolites were mainly involved in several metabolic pathways,including glycolysis (lactic acid,alaline),serine metabolism (serine,phosphoserine),proline metabolism (proline),glutamic acid metabolism,tricarboxylic acid cycle (succinate,malic acid),nucleotide metabolism (pyrimidine),fatty acid metabolism (docosanoic acid,and octadecanoic acid),and methylation(glycine).The serine and proline metabolisms were highlighted during the progression of metastasis.CONCLUSION:Proline and serine metabolisms play an important role in metastasis.The metabolic profiling of tumor tissue can provide new biomarkers for the treatment of gastric cancer metastasis.

Gas chromatography/mass spectrometry based metabolomic study in a murine model of irritable bowel syndrome

AIM To study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome(IBS).METHODS In the current study, using a metabolomic approach, we analyzed the key metabolites differentially excreted in the feces of control mice and mice with IBS, with or without Clostridium butyricum(C. butyricum) treatment. C57 BL/6 mice were divided into control, IBS, and IBS + C. butyricum groups. In the IBS and IBS + C. butyricum groups, the mice were subjected to water avoidance stress(WAS) for 1 h/d for ten days. Gas chromatography/mass spectrometry(GC-MS) together with multivariate analysis was employed to compare the fecal samples between groups. RESULTS WAS exposure established an appropriate model of IBS in mice, with symptoms of visceral hyperalgesia and diarrhea. The differences in the metabolite profiles between the control group and IBS group significantly changed with the progression of IBS(days 0, 5, 10, and 17). A total of 14 differentially excreted metabolites were identified between the control and IBS groups, and phenylethylamine was a major metabolite induced by stress. In addition, phenylalanine metabolism was found to be the most relevant metabolic pathway. Between the IBS group and IBS + C. butyricum group, 10 differentially excreted metabolites were identified. Among these, pantothenate and coenzyme A(Co A) biosynthesis metabolites, as well as steroid hormone biosynthesis metabolites were identified as significantly relevant metabolic pathways.CONCLUSION The metabolic profile of IBS mice is significantly altered compared to control mice. Supplementation with C. butyricum to IBS mice may provide a considerable benefit by modulating host metabolism.

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.

Analysis of residual crosslinking agent content in UV cross-linked poly(ethylene oxide) hydrogels for dermatological application by gas chromatography

Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively inert, causing no irritation and allergies. Poly(ethylene oxide)(PEO) hydrogels were prepared using pentaerythritol tetra-acrylate(PETRA) as UV crosslinking agent. A simple, accurate, and robust quantitation method was developed based on gas chromatographic techniques(GC), which is suitable for routine analysis of residual PETRA monomers in these hydrogels. Unreacted PETRA was initially identified using gas chromatography–mass spectrometry(GC–MS). The quantitation of analyte was performed and validated using gas chromatography equipped with a flame ionization detector(GC–FID). A linear relationship was obtained over the range of 0.0002%–0.0450%(m/m) with a correlation coefficient(r2)greater than 0.99. The recovery( 4 90%), intra-day precision(%RSD o 0.67), inter-day precision(%RSD o2.5%), and robustness(%RSD o1.62%) of the method were within the acceptable values. The limit of detection(LOD) and limit of quantitation(LOQ) were 0.0001%(m/m) and 0.0002%(m/m), respectively.This assay provides a simple and quick way of screening for residual acrylate monomer in hydrogels.

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.

Product Analysis of Supercritical Fischer-Tropsch Synthesis: Utilizing a Unique On-Line and Off-Line Gas Chromatographs Setup in a Bench-Scale Reactor Unit

The utilization of supercritical fluids (SCF) in the Fischer-Tropsch Synthesis (FTS) further complicates the hydrocarbon products identification and analysis process due to the dilution of hydrocarbon peaks by the predominant solvent peak. Therefore, in this project, a custom-made Gas Chromatography (GC) analysis system was designed and implemented to identify and quantify SCF-FTS products. The FTS products were identified using two different methods. The first was through retention time matching by injecting standard solutions, and the second was through the use of the GC/MS system. The quantification of CO and CH4 was achieved by using external standards, where the CO conversion was calculated by relating the peak area of CO to the peak area of an internal standard (argon) while the CH4 selectivity was calculated by relating the peak area of CH4 to that of CO. After setting and calibrating the GC system, two reaction conditions (gas phase: 240°C, 20 bar syngas with 2:1 H2:CO molar feed ratio and for the supercritical fluids FTS (SCF-FTS): 240°C, 65 bar with 20 bar syngas partial pressure and 2:1 H2:CO molar feed ratio) were used to compare the different FTS reaction media. The comparison between the gas phase FTS and the SCF-FTS showed the following: carbon monoxide conversion was improved by 14% in the SCF-FTS, while the hydrocarbon product profile SCF-FTS showed 78% reduction in light hydrocarbons (C1 - C4) products, 35% increase in middle distillates (C11 - C22) products compared to gas phase FTS. These improvements have resulted in higher chain growth probability for the SCF-FTS (α = 0.85) compared to the gas phase FTS (α = 0.76). These results are generally in agreement with previously reported enhancement in the SCF-FTS[1].

固相萃取-GC-MS法测定饲料中的沙丁胺醇

沙丁胺醇(salbutamol),化学名称1-(4-羟基-3-羟甲基苯基)-2-(叔丁氨基)乙醇(结构式如图1所示),俗称舒喘宁,属于β-兴奋剂类药物的一种,临床上用于治疗支气管哮喘.同时沙丁胺醇同克伦特罗(瘦肉精)一样还具有提高饲料的转化率,促进动物生长的作用.但是,这种药物容易在动物内脏、组织中蓄积残留,有很大的副作用.……

广防己挥发油的GC-MS指纹图谱研究

防己药材主要分粉防己和木防己两类,木防己包括广防己和汉中防己.广防己为马兜铃科植物广防己Aristolochia fangchi Y.C.WuexL.D.Chou.et S.M.Hwang的干燥根[1],习称"木防己"、"水防己",主产于广东、广西,具有祛风止痛、清热利水之功效[2].……

GC-MS测定家犬血浆中银杏内酯A、B的含量

银杏叶制剂作为治疗和预防动脉粥样硬化的有效药物,越来越为人们关注.银杏叶成分复杂,其中银杏黄酮具有扩张血管,降血脂,改善微循环的作用;银杏内酯是血小板活化因子强拮抗剂,对免疫系统,中枢神经系统,缺血损伤有保护作用,并有抗休克、抗过敏及抗炎作用.由于银杏内酯含量较低,对其进行的药动力学研究较少,且多采用的是非特异性的生物测定方法.……

Exploring Chemovar-Specific Cannabis Extracts Quantification and Evaluation of Cytotoxic Compounds for Targeting Glioblastoma Multiforme

Glioblastoma Multiforme (GBM) represents one of the most aggressive and metastatic brain tumors, with a dismal success rate of less than three percent after five years, particularly in tumors with active immune checkpoints. This necessitates the development of targeted endogenous agents for precise GBM treatment. Previous experiments utilizing Chemovar Specific Cannabis Extractions (CSCEs), fractionated with polar solvents and quantified using Liquid and Gas Column Chromatography combined with Mass Spectrometry (LC/GCMS), have shown reduced viability and motility in human GBM cell lines. However, the complexity of the botanical substance has hindered the personalization of standard cannabis medicines for GBM due to unknown synergistic effects of multiple compounds. To address this limitation, our study focuses on exposing AM251 cells to chemovar fractions extracted using a non-polar solvent, thereby isolating a broader spectrum of constituents. By employing LC/GCMS in conjunction with Nuclear Magnetic Resonance (NMR), we have identified and quantified nine* compounds present in the non-polar CSCE that exhibit significant efficacy (0.1 μM) in inducing cytotoxicity* in GBM tumor cells. Conversely, the polar fraction in our experiment did not demonstrate efficacy against UM251 cells. The quantification of individual compounds within a cannabis extraction that selectively induces cell death in brain tumors holds promise for guiding future research and facilitating the development of a standardized CSCE for GBM therapy.

衍生固相萃取GC-MS检测牛可食组织中克伦特罗的残留量

盐酸克伦特罗(clenbuterol,CLB),俗名"瘦肉精",化学名为"2-[(叔丁氨基)甲基]-4-氨基-3,5-二氯苯甲醇盐酸盐"(相对分子质量313.5),是一种β-兴奋剂[1].近年来动物性产品中CLB残留对人类健康造成的危害和对生态食物链所造成的破坏已经引起高度重视.……

热裂解气相色谱-质谱研究阻燃纤维的结构及烟雾毒性

随着高分子材料的不断开发,涌现出一大批用于阻燃和热辐射防护的耐高温纤维,如Basofil、Kermel、Visil、Nomex、P84、PBI和PBO等纤维,除了在衣着领域的应用外,在消防服、工业用阻燃防护服以及汽车等的内装饰物和家用防火材料等方面,具有更优异的防护功能和穿着舒适性.……