Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

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.

Gas Chromatographic Method for Identification and Quantification of Commonly Used Residual Solvents in Pharmaceuticals Products

Background: Impurities are not expected in the final pharmaceutical products. All impurities should be regulated in both drug substances and drug products in accordance with pharmacopeias and ICH guidelines. Three different types of impurities are generally available in the pharmaceutical’s product specification: organic impurities, inorganic impurities, and residual solvents. Residual solvents are organic volatile chemicals used or generated during the manufacturing of drug substances or drug products. Purpose: The aim of this study is to develop a cost-effective gas chromatographic method for the identification and quantification of some commonly used solvents—methanol, acetone, isopropyl alcohol (IPA), methylene chloride, ethyl acetate, tetrahydrofuran (THF), benzene, toluene, and pyridine—in pharmaceutical product manufacturing. This method will be able to identify and quantify the multiple solvents within a single gas chromatographic procedure. Method: A gas chromatography (GC) equipped with a headspace sampler and a flame ionization detector, and a column DB 624, 30-meter-long × 0.32-millimeter internal diameter, 1,8 μm-thick, Brand-Agilent was used to develop this method. The initial GC oven temperature was 40°C and held for 5 minutes. It was then increase to 80˚C at a rate of 2˚C per minute, followed by a further increase to 225˚C at a rate of 30˚C per minute, with a final hold at 225˚C for 10 minutes. Nitrogen was used as a carrier gas at a flow rate of 1.20 mL per minute. Dimethyl sulfoxide (DMSO) was selected as sample solvent. Results: The developed method is precise and specific. The percent RSD for the areas of six replicate injections of this gas chromatographic method was within 10.0 and the recovery result found within 80.0% to 120.0%.

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.

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.

Determination of 7 Indictor Polychlorinated Biphenyls (PCBs) Residues in Porphyra by Ultrasonic Extraction and Gas Chromatography (GC)

A method was developed for determination of 7 indictors the polychlorinated biphenyls (PCBs) residues in porphyra by gas chromatography (GC) with electron capture detector (ECD). The PCBs were extracted with hexane/methylene chloride (1:1, v/v) by ultrasonic extraction and the samples were cleaned up by concentrated sulfuric acid and Alumina-N solid phase extraction cartridge. The analytes were quantified by an internal standard method. Under optimal experimental conditions, good linearity was observed in the range of 5 - 200 ng/mL and the correlation coefficients were 0.9994 - 0.9998. The limit of quantitation (LOQ) for target analytes ranged from 6.0 to 10.0 μg/kg. At the spiked levels of 10, 50, 100 μg/kg, the average recoveries ranged from 90.9% to 102% with the relative standard deviations 2.12% - 6.32%. The result showed that the proposed method was rapid, and could be used for the determination of the PCBs in porphyra.

Classification of Chinese Traditional Drug-"Beimu" (Bulbus Fritillariae) by Pyrolysis High Resolution Gas Chromatography-Pattern Recognition

The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples of five different geographic origins: Eastern China.Central China.South-western China,North-western China and North-eastern China.Principal component analysis and SIMCA are applied to effectively classifying the samples according to the origin of the plants.The chemical information contained in the high resolution gas chromatographic data is sufficient to characterize the geographic origin of sam- pies.

Determination of phthalate esters in fat-containing foods by packed nanofiber solid-phase extraction column and gas chromatography

A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.

Determination of Dichlofluanid Residue in Soybean by Capillary Collumns Gas Chromatography

A method for the determination of dichlofluanid residue by Capillary Collumns Gas Chromatography was established in this study.Samples were extracted with acetone and subjected to through liquid-liquid extraction with N-hexane,and then they were cleanup with column that filled with florisil,subsequently separated by Capillary Column Gas Chromatography,and the electron capture detector （ECD） was used for detection.The detection limit of this method was 0.005 mg/kg （S/N=3）,and this method was rapid,sensitive and accurate,and was applied in the determination of dichlofluanid residue in soybean.

Separation Properties of a New Polysiloxane-Anchored β-Cyclodextrin Derivative as Gas Chromatography Stationary Phase

A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It exhibited separation abilities to disubstituted benzene isomers and some chiral solutes. It was also found that the polarity of CD derivatives can be lowered both by chemically bonding it to polysiloxane and by diluting it in polysiloxane. The separation abilities of the polysiloxane anchored CDs (SP CD) are higher than that of the unbonded CDs (S CD) and the diluted S CD at lower column temperature. Hydrosilylation reaction is one of the best methods to lower the operating temperature of CDs.

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.

Synthesis and Characterization of Peralkylated β-Cyclodextrins Used as Gas Chromatographic Stationary Phasest

Six peralkylated β- cyclodec\xtrins used as capillary gas chromatographic stationary phases were prepared and characterized by differential by differential scannning calorimetry(DSC) and pyrolysis gas chromatography (PyGC). The DSC profiles illustrated that the peralkylated β-cyclodextrins synthesized possess the supercoooled state and the glass state below their melting point The PYGC results showed that the long-chain alkylated β-cyclodextrins are more thermostable than the short-chain. one All ofthese peralkylated β-cyclodextrins are suitable for use as capillary column gas chromatographic stationary phases,which can easily be coatal on the fused silica capilary columns and have nice chromatographic retention behaviour. For example, the capillary colunns coated with these materials can excellently separate three methylphenol isomers and six dimehylphenol isomers.

Application of Pyrolysis-Gas Chromatography in Explosive and Propellant Analysis

Applications of pyrolysis-gas chromatography and pyrolysis capillary gas chromatography in explosive and propellant analysis are reviewed, including the identification of explosives and propel- lants, the investigation of the thermal decomposition of nitrocellulose (NC), cyclotetramethylene tetranitramine (HMX)and cyclotrimethylene trinitramine (RDX), and the study of the wear- reducing mechanism of polyurethane additive in propellant gain.

基于GC-IMS和GC-MS技术结合化学计量法分析干燥方式对香椿挥发性成分的影响

为研究干燥方式对香椿挥发性风味物质的影响,利用气相色谱-离子迁移谱技术(gaschromatography-ion mobility spectrometry,GC-IMS)和气相色谱-质谱联用技术(gas chromatography-mass spectrometry,GC-MS)、相对香气活性值(relative odor activity value,ROAV)对真空冷冻干燥、热泵干燥、热风干燥、微波真空干燥的香椿样品进行挥发性成分分析,并进一步结合化学计量方法主成分分析(principal component analysis,PCA)和偏最小二乘判别分析(partial least squares-discriminant analysis,PLS-DA),探究样品间挥发性成分的差异性。结果表明,通过GC-IMS检测到78个峰,鉴定出59种化合物。通过GC-MS鉴定出94种挥发性化合物,主要挥发性成分是硫化物、烯烃类和醛类。经过干燥后总挥发性化合物的含量显著降低。通过ROAV法确定了(E,Z)-二-1-丙烯基二硫化物、2-巯基-3,4-二甲基-2,3-二氢噻吩、正己醛、2-己烯醛、丁香酚等为香椿样品中关键香气化合物。PCA和PLS-DA结果表明,不同干燥方式的样品与新鲜样品有明显的分离,彼此之间也有明显的区别。鲜样和真空冷冻干燥样品为一组,其他3个干燥香椿样品为一组。根据变量投影重要性(variable importance in projection,VIP)得分共筛选出10种(VIP>1)标志挥发性化合物。干燥方式对香椿风味特性影响显著,真空冷冻干燥组与鲜样最为接近,考虑实际应用热泵干燥为香椿最适宜的脱水方式。本研究为热加工过程中风味品质控制提供一定的理论参考。

GC-MS结合电子鼻技术对不同茶区茉莉花茶香气的差异比较

为探究不同产区茉莉花茶香气差异,采用气相色谱-质谱(GasChromatography-Mass Spectrometry,GC-MS)结合电子鼻(Electronic Nose,E-nose)技术对西南、华南、江南三大茶区的8种茉莉花茶进行香气研究。结果表明,8个样品共鉴定出香气成分58种,其中西南、江南、华南茶区分别为45种、51种、47种。江南茶区香气化合物总量最高。共有香气成分主要包括邻氨基苯甲酸甲酯、顺式-3-己烯醇苯甲酸酯、乙酸苄酯、水杨酸甲酯、芳樟醇、吲哚等。其中水杨酸甲酯在江南茶区含量最高(22.32μg/g),分别较华南、西南茶区高33.96%、68.01%;邻氨基苯甲酸甲酯(67.39μg/g)和吲哚(43.84μg/g)含量在华南茶区最高。茉莉花茶香气评价指数(JasmineTea Flavor Index,JTF index)分析表明西南茶区样品等级最高。香气聚类分析将共有香气成分分为3类,分别呈花香、茉莉花香和草木香。通过电子鼻技术可知样品香气物质变化与硫化物、碳氢化合物、芳香化合物有关,并能有效区别样品香气。综上,三大茶区样品香气种类差异不明显,但各香气成分含量差异显著(P<0.05),江南和华南茶区的样品特征性香气成分含量较高,西南茶区样品综合指数高。

硅烷衍生化GC-MS检测香精中糖类物质成分

建立了基于硅烷衍生化气相色谱-质谱联用法快速检测香精中17种糖类物质的方法。结果表明:衍生化的最佳条件为以BSTFA为衍生化试剂、衍生化温度40℃、衍生化时间40 min,在此条件下共鉴定出17种糖类物质。17种糖类物质在一定质量浓度内具有良好的线性关系(R^(2)>0.99)。方法的检出限为0.027~0.077μg/mL,加标回收率为94.80%~110.03%,相对标准偏差为3.03%~8.06%。实际样品测定结果表明,建立的方法能够快速准确地检测香精中17种糖类物质成分,满足对香精中糖类物质的同时检测。

不同厂家水基胶挥发性物质的GC-IMS差异分析

目的快速分析不同厂家水基胶中的挥发物特性。方法采用气相色谱-离子迁移谱(GC-IMS)联用技术对各种水基胶中的挥发性物质进行定性分析;结合生物指纹图谱、主成分分析(PCA)法以及欧式距离分析法对不同水基胶样品进行差异对比分析。结果水基胶中共识别出88种挥发性化学物质,涵盖酯类、酮类、醇类、醛类、杂环类、酸类、芳香类、醚类、萜类、酰胺类和腈类等11大类别,其中酯类物质占据显著比例,达26种,占总挥发性物质的38%~46%。结论采用GC-IMS技术结合生物指纹图谱、PCA以及欧式距离分析,能够有效区分不同厂家水基胶样品,同时同一厂家不同规格样品之间显示出较高的相似性;GC-IMS技术为不同厂家水基胶的快速溯源鉴别及挥发性物质差异分析提供了有力工具。

Enantioselective Determination of R-(-)-and S-(+)-Mexiletine in Microsomal Incubates by Capillary gas Chromatography

A method for the assay of R ( ) and S (+) mexiletine in rat liver microsomal incubates was developed. The method involved extraction of mexiletine from the microsomal incubates, and formation of mexiletine diastereomeric derivatives with a chiral reagent S ( ) N trifluoroacetyl prolyl chloride. Separation and quantitation of the diastereomeric mexiletine derivatives were carried out by a capillary gas chromatographic system with flame ionization detection. The assay was linear from 5 to 500 μg/ml for each enantiomer. The average recoveries of analytical method were 93 31±5 59% and 93 10±5 11% for R ( ) and S (+) mexiletine, respectively. The limits of detection and quantitation for the method were 1 0 μg/ml and 5 0 μg/ml for the R ( ) and S (+) mexiletine isomers, respectively. The reproducibility in the assay was better than 16.5% (RSD). The method has been applied to the metabolism study of R ( ) and S (+) mexiletine in rat liver microsomal incubates.

托里阿魏挥发油的GC-MS指纹图谱及抗宫颈癌作用研究

目的建立托里阿魏挥发油的气相色谱-质谱(GC-MS)指纹图谱,并考察托里阿魏挥发油的抗宫颈癌作用。方法采用有机溶剂提取法提取托里阿魏根的挥发油,并通过GC-MS鉴定所含成分。通过MTT比色法考察不同浓度托里阿魏挥发油对人宫颈癌Hela细胞增殖的抑制作用。采用Transwell法检测托里阿魏挥发油对人宫颈癌Hela细胞迁移、侵袭能力的影响。应用流式细胞术检测托里阿魏挥发油作用下的细胞凋亡率。结果托里阿魏挥发油中鉴别出58种化学成分,含量最多的是孕酮。托里阿魏挥发油对人宫颈癌Hela细胞的增殖有一定的抑制作用,IC50为55.21μg/ml。托里阿魏高、低剂量组与对照组相比,迁移和侵袭细胞数量显著减少(P<0.01)。结论托里阿魏挥发油中含量最高的是酮类化合物。托里阿魏提取物有一定的抗肿瘤作用。

快速高效区分黄檀属黑酸枝木的方法-GC/MS指纹图谱

采用气相色谱-质谱指纹图谱分别鉴定阔叶黄檀、卢氏黑黄檀、东非黑黄檀和伯利兹黄檀木材。以二氯甲烷提取样品中的特定化合物,采用气相色谱-质谱法分析提取物,建立目标物色谱图。采用二氯甲烷溶剂提取阔叶黄檀、卢氏黑黄檀、东非黑黄檀和伯利兹黄檀4种黄檀属黑酸枝木,其提取液用气相色谱质谱联用仪分析,结果显示该4种树种的特征色谱峰不同。阔叶黄檀的色谱峰在14.6min、14.8min出现双子色谱峰,强度相似;卢氏黑黄檀分别在11.9min、12.5min、12.9min有3个强度相似的色谱峰;东非黑黄檀的强度大的特征峰在18.3min和18.5min;伯利兹黄檀仅有1个强度大的色谱峰,其保留时间在17.1min。分析这4种木材的GC/MS指纹图谱,色谱峰的保留时间不同。该方法可以有效区分鉴别这4种黑酸枝木。