Determination of volatile components in cut tobacco with gas chromatography-mass spectrometry and chemometric resolution

Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation and extraction method,the volatile components in cut tobacco were detected by GC-MS.Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms.The qualitative analysis was performed by similarity searches in the national institute of standards and technology(NIST)mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response.The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra.107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified,accounting for about 88.01% of the total content.The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.     

Simulation of pipelining pours point depressant beneficiated waxy crude oil through China West Crude Oil Pipeline

Flow properties of waxy crude oils,particularly the beneficiated waxy crude oils,are sensitive to shear history that the crude oil experienced,called the shear history effect.To simulate this shear history effect accurately is vital to pipeline design and operation.It has been demonstrated by our previous that the energy dissipation or entropy generation due to viscous flow in the shear process is a suitable parameter for simulating the shear history effect.In order to further verify the reliability of this approach,experimental simulations were conducted for three PPD-beneficiated waxy crude oils transported through the China West Crude Oil Pipeline,a most complicated long-distance-crude-oil-pipeline technically and operationally so far in China.The simulations were made by using a stirred vessel and with the energy dissipation of viscous flow as the shear simulation parameter.Comparison between the flow properties of crude oils obtained from field test and experimental simulations,it is found that the gel points and viscosities from experimental simulations are in good agreement with the field data.     

Analysis of volatile components in herbal pair herba schizonepetae-ramulus cinnamomi

Analysis of volatile components in herbal pair （HP） herba schizonepetae-ramulus cinnamomi （HS-RC）, single herb HS and RC was carried out by gas chromatography-mass spectrometry （GC-MS） data and chemometric resolution method （CRM）. The two-dimensional data obtained from GC-MS instruments were resolved into a pure chromatogram and a mass spectrum of each chemical compound by CRM. In total, 47, 61 and 51 chemical components in volatile oil of HS, RC, and HP HS-RC were respectively determined qualitatively and quantitatively, accounting for 90.52%, 88.37%, and 88.72% total contents of volatile oil of HS, RC, and HP HS-RC, respectively. The number of the volatile components of HP HS-RC is almost the addition of that of two single herbs, but their relative contents are changed.     

Preparation of tungsten disulfide motor oil and its tribological characteristics

Through using mineral oil and synthetic oil to deploy the semisynthesis base oil, modifying the surfaces of ultrafine tungsten disulfide grains by surface chemical embellishment and adsorption embellishment to make them suspended steadily in the base oil as solid lubricating additive, and adding some function additives, the tungsten disulfide motor oil was prepared. The tribological characteristics of this kind motor oil and the well-known motor oils in our country and overseas were studied. The results show that the oil film strength of this kind of motor oil is respectively 1.06 and 1.38 times of that of shell helix ultra motor oil and great wall motor oil, and its sintering load is 1.75 and 2.33 times of that of them, and when tested under 392 N, 1 450 r/min and 30 min, the friction coefficients of friction pairs lubricated by the tungsten disulfide motor oil decrease with the increase of time, meanwhile, the diameter of worn spot is small, and the surface of worn spot is smooth, and no obvious furrows appear. The experiments indicate that the tungsten disulfide motor oil has the better antiwear, antifriction and extreme pressure properties than the well-known motor oils.     

Systematically structural identification of nitriccompounds in crude oil with chemometric resolution

Aimed at the problem of classification of non-hydrocarbons of crude oil, the theoretical standpoint that the polarity of a compound depends on the whole structure and composition of molecule instead of a kind of heteroatom or its functional group was presented. A method was established for the systematically structural identification of nitric compounds in crude oil. The pre-fractionation of a crude oil sample into 7 fractions was performed by diadsorption column chromatography with neutral aluminum oxide and silica gel. Subsequently, the individual components were obtained by using capillary column gas chromatography, and the types of compounds were detected by a mass spectrometer. In combination with a chemometric resolution, the compounds of fraction were further identified. This method can relieve the difficulty of classical analysis in identifying those species with very low contents or without being completely separated. The structures of 168 nitric compounds in a crude oil sample were determined by this method.     

Tribological Properties of MoSi2 Against AISI10045 Steel Under Sliding Friction

MoSi2 samples were prepared by a self-propagating high-temperature synthesis （SHS） and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1） oil lubrication can obviously improve the tribological properties of MoSi2, 2） the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3） with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4） under oil lubrication the wear mechanism is mainly fatigue pitting.     

Effects of postthermal treatment and UV irradiation on the structure of titania-polyacrylate nanocomposites

The effects of postthermal treatment and irradiation time on the structure and thermal stability of TiO2/polyacrylate nanocomposites by a sol-gel process in reverse micelles and subsequent rapid photopolymerization were investigated, and the hybrid films were characterized by thermal gravimetry analysis （TGA）, X-ray photoelectron spectrum （XPS）, and atomic force microscopy （AFM）. XPS data suggested that the prolongation of irradiation time and the postthermal treatment promoted titania formation, with the former affecting more remarkably. TGA data showed that TiO2-hybrid films could upgrade the decomposition onset temperature （Tonset） as well as the temperature at which there is a maximum mass loss rate （Tmax）. AFM data demonstrated that the inorganic titania particles with a mean diameter of 25.26-28.84 nm were homogeneously distributed in the organic matrix.     

The Synthesis and Eleetrorheologieal Properties of BaTiO3-coated PMMA Mierospheres

Coated-PMMA microspheres consisting of poly （methyl methacrylate）（PMMA） core and barium titanate （BaTiO3） shell were synthesized by the modified sol-gel processing and then adopted as an electrorheological （ER） materials. The structure and morphology of coated powders were chyfecterized by SEM and FT-IR; the shear stress of the suspensions of coated-PMMA particles and pure PMMA particles in silicone oil with a 20 vol% were investigated. The results show that the BaTiO3 coated PMMA microspheres based suspension in silicone oil exhibited typical ER behavior and stronger ER effects.     

Lubrication in strip cold rolling process

A lubrication model was developed for explaining how to form an oil film in the deformation zone, predicting the film thickness and determining the characteristics of lubrication in the strip rolling process, combined with the knowledge of hydrodynamic lubrication and rolling theories. Various mineral oils with viscosities from 0.032 to 1.6 Pa.s were used to obtain different film thicknesses in the strip cold rolling. Results from the experiment and calculation show that the oil film forming in hydrodynamic lubrication is up to the bit angle and a higher rolling speed or a higher rolling oil viscosity. The mechanism of mechanical entrainment always affects the film thickness that increases with the rolling oil viscosity increasing or the reduction rate decreasing in rolling.     

Characteristics of Chang 2^1 Low Permeability Sandstone Reservoir in Shunning Oil Field

Characteristics of Chang 2^1 low permeability sandstone reservoir of Shunning oil field are analyzed and evaluated based on the data of well logging and experiment. The result shows that 1） the Chang 2^1 low permeability reservoir belongs to the classification of middle-to-fine sized feldspar sandstone, with its components being low in maturity, deposited in distributary rivers in the front of the delta; 2） the reservoir is obviously dominated by a low or a very low permeability with a linear variation tendency different from that of the ultra-low permeability reservoir; 3） the spatial variation in lithology and physical properties of the reservoir are controlled by the sedimentary facies zones, and 4） the physical property of the reservoir is significantly influenced by clastic constituents and their structure, and the constituent of cement materials and their content. The result also shows that the diagenesis action of the reservoir is quite strong in which dissolution greatly modified the reservoir In addition, the inter-granular dissolved pores are the mainly developed ones and the micro-structure is dominated by the combination of middle-to-large sized pores with fine-to-coarse throats. Finally, the radius of the throats is in good exponential correlation with permeability and the seepage capacity comes from those large sized throats.     

Determination of constituents of essential oil from Angelica sinensis by gas chromatographymass spectrometry

1INTRODUCTION TraditionalChinesemedicines(TCMs)are veryimportantduetotheirextensiveuseinpre ventingandcuringmanydiseasesforhumans.Al thoughonlysomecompoundsmightberesponsible forpharmaceuticaleffects,traditionalChinese medicinesusuallycontaintoomanycomponentsandformaverycomplexsystem,whichmakesthe screeningandanalysisofbioactivecomponentsex tremelydifficult[1]comparedwiththoseofwesternmedicines.Whensuchcomplexsamplesareana lyzed,itiscommonthatdifferentcontentsof multi componentsandgreatd…     

野菊菊米和野菊花挥发油化学成分的比较研究

采用水蒸气蒸馏法提取云南产野菊菊米和野菊花挥发油，用气相色谱-质谱联用技术对其化学成分进行分离鉴定，并用面积归一化法测定了相对含量．鉴定出野菊菊米主要化学成分50种，占总化合物的95．00％；野菊花主要化学成分42种，占总化合物的90．95％．野菊菊米和野菊花挥发油的主要成分为单萜烯类、倍半萜烯类及其含氧衍生物等，但其化学成分种类和含量有明显的差别．     

长春七根部挥发油的测定及抑菌活性研究

研究了长春七根部挥发油的提取方法,结合该部位的抑菌活性测试,提高挥发油的综合利用价值. 采用挥发器测定和索式抽提两种方法和不同溶剂分别对长春七根部进行挥发油的提取,通过GC-MS联用技术测定分析有效成分,并进行比对,同时测试了其对大肠杆菌和金黄色葡萄球菌的抑菌活性. 结果表明,两种方法的提取率和提取成分的种类与含量存在差异. 抑菌活性测试表明长春七根部挥发油对大肠杆菌和金黄色葡萄球菌均能产生明显的抑制作用. 两种方法可以互补地用于长春七根部中的有效成分的提取,结合挥发油的抑菌活性,进一步明确了该部位的应用前景.     

超声波提取牡荆挥发油化学成分的GC-MS分析

采用超声波法提取牡荆挥发油,运用毛细管气相色谱-质谱联用法,对其化学成分分别进行分析和鉴定,共鉴定出21个化合物,并用面积归一化法测定各化合物在挥发油中的相对含量。其中挥发油的主要成分确定为十六酸(15.9%)、邻苯二甲酸异丁基酯(14.43%)、苯酚(13.61%)、雪松醇(4.08%).本研究为牡荆的开发利用提供了实验依据。     

Chemical component and antimicrobial activity of volatile oil of Calycopteris floribunda

The volatile oil of leaves and barks of Calycopteris floribunda was examined by gas chromatography-mass spectrometry (GC-MS). 52 volatile chemical components in leaves were identified. The antimicrobial assay of oils in the leaves and barks was carried out by disk diffusion method in vitro. The major components (mass fraction) in leaves are caryophyllene oxide (13.79%), n-hexadecanoic acid (11.91%) and β-caryophyllene (10.45%). Ten constituents are identified accounting for about 99.98% of the total volatile oil in the bark. Among these components, n-hexadecanoic acid (59.18%), linolic acid (12.70%) and butyl octyl phthalate (8.21%) are the major constituents. The oils exhibit strong antimicrobial activity and display more potent against bacteria than fungi.     

冠心丹参片中降香挥发油鉴别和成分分析

为对冠心丹参片中降香油进行定性分析及降香油主要化学成分的分析测定,用薄层色谱法进行定性鉴别,用气质联用技术分离和鉴定各化学组分,用离子流色谱峰面积归一法计算各化学组分的相对含量。结果显示,在薄层色谱鉴别显示冠心丹参片样品色谱中,与降香油对照品色谱相应的位置上显相同颜色的斑点。气质联用分析分离出25个化学组分峰,并鉴定其中10个化学成分和计算各组分的相对含量。由此得出,利用薄层色谱法和气质联用分析法可以有效鉴别冠心丹参片中降香挥发油的有效成分,主要有效成分为橙花叔醇,含量为42.01%.     

曼地亚红豆杉枝叶挥发油化学成分的GC-MS分析

采用多种方法提取了曼地亚红豆杉混合枝叶和单独的枝干或叶中的挥发油,并用气相色谱-质谱（GC-MS）方法对它们的化学成分进行鉴定,用面积归一法测定了各组分的百分含量。实验表明：采用微波辅助水蒸气蒸馏法、微波辅助溶剂提取法、超声波辅助溶剂提取法和溶剂加热回流提取法分别提取曼地亚红豆杉混合枝叶中挥发油,其中分别鉴定出27、26、13及20种成分;运用溶剂加热回流提取法从曼地亚红豆杉单独的枝干和叶中提取的挥发油中可分别鉴定出16和24种成分,挥发油得率分别为4.21%和9.70%。从实验结果可知：不同提取工艺所得曼地亚红豆杉枝叶中挥发油种类差异较大,且叶中挥发油含量明显高于枝干。     

玫瑰香精油化学成分分析

应用气相色谱-质谱联用(GC/MS)方法,定性定量地分析了山东平阴玫瑰精油、新疆玫瑰精油、北京妙峰山玫瑰精油和保加利亚玫瑰精油的化学成分,各鉴定了29、37、23和24个成分.它们的主要成分均为香茅醇及其脂类、香叶醇、芳樟醇、玫瑰醚和丁香酚,其中北京妙峰山玫瑰油与其他油品有较大差异.各种香精物质含量上的差异使得这几种玫瑰油的香气产生了微妙的出入.详细地讨论了这4种玫瑰油的化学成分与香气间的关系,指出国内玫瑰油的不足之处,为提升我国玫瑰精油的品质提供借鉴和依据.     

不同部位北香薷挥发油的制备及化学成分分析

目的：研究花、茎、叶不同部位北香薷挥发油的制备及化学成分分析。方法：采用水蒸气蒸馏法制备挥发油,运用气相色谱-质谱(GC-MS)技术鉴定香薷挥发油的化学成分,纸片法考察抑菌活性。结果：GC-MS分析鉴定出香薷花、茎、叶成分含量较高的分别为BETA-去氢香薷酮、1,1'-[亚乙基双(氧基)]二丁烷、BETA-去氢香薷酮,抑菌试验。结果表明北香薷三个部位对金黄色葡萄球菌、枯草和短小芽孢杆菌、白色念珠菌有不同程度抑制作用。结论：北香薷不同部位挥发油的化学成分不同、抑菌活性也有差异,本研究为北香薷挥发油的开发利用提供依据。     

微波辅助水蒸汽蒸馏樟树叶挥发油的研究

采用微波辅助水蒸汽蒸馏方法和传统水蒸汽蒸馏方法提取樟树叶挥发油,用色谱-质谱联用分析鉴定,并用GC-MS总离子流色谱峰的峰面积归一化法对挥发油成分进行定量分析.实验结果表明,微波辅助水蒸汽蒸馏方法与传统水蒸汽蒸馏所得的挥发油成分基本相同,但微波辅助水蒸汽蒸馏的挥发油收率(1.15%)高于水蒸汽蒸馏挥发油的收率(0.96%).自制的微波辅助水蒸汽蒸馏装置,具有价格便宜,容易推广使用等优点,同时在该装置基础上进行的微波辅助水蒸汽蒸馏方法是一种真正意义上的无污染、快速,且具有高收率的提取鲜活香料植物挥发油的萃取新技术.