猪油挥发油成分的气相色谱/质谱法分析

1　引　　言油脂是人类的主要食品之一 ,其主要成分是脂肪酸甘油三酯 ,它参与人体正常生理代谢。油脂香气成分是其微量成分 ,含量一般在油脂总量的 1%以下 ,却构成其各自特征香气。奶油、玉米油、牛油等均有较详细的报道。本文以ＧＣ ＭＳ分析猪油香气成分 ,70种成分被确定。2　实验部分2 .1　主要仪器　ＨＰ5 973气质联用仪 (ＧＣ ＭＳ) ,ＨＰＩＮＮＯＷＡＸ 30ｍ× 0 .2 5ｍｍ× 0 .2 5 μｍ毛细管柱 ,ＮＩＳＴ98谱库。2 .2　ＧＣ ＭＳ条件　进样口温度 2 5 0℃ ,检测器温度 2 80℃ ,柱温 6 0℃ (2ｍｉｎ) 2℃ ｍｉｎ12 0℃ (1ｍｉｎ) 10…     

基体辅助激光解吸电离飞行时间质谱和热裂解色谱／质谱研究聚酯 …

聚酯型聚氨酯样品用基体辅助激光裂解离子化质谱（ＭＡＬＤＩ－ＴＯＦ／ＭＳ）和热裂解色谱质谱（ＰＹＧＣ／ＭＳ）方法进行了鉴定,ＰＹＧＣ／ＭＳ方法可检出ＰＵ的一些组成单元的化学结构,但ＰＹＧＣ／ＭＳ中大多数的峰,无法从常规的标准化合物的质谱数据库中检索到,而ＭＡＬＤＩ－ＭＳ方法,可明确测出ＰＵ试样各种单元的组合、聚合度及ＰＵ长链的序列分布,质量数范围可达２３００。     

韭菜花挥发性成分的气相色谱-质谱分析

1　实验部分1.1　仪器　　ＨＰ5890气相色谱 ＨＰ5970Ｂ质量检测器;ＳＥ 54弹性石英毛细管柱(30ｍ×0 25ｍｍｉ.ｄ.,0 25μｍ);蒸馏 萃取器(海门玻璃仪器厂产品[1])。1.2　气相色谱 质谱(ＧＣ ＭＳ)条件　　柱温:初始40℃,保持2ｍｉｎ,以4℃/ｍｉｎ升至160℃,以8℃/ｍｉｎ升至250℃,保持31 25ｍｉｎ;进样口温度250℃;转移线温度280℃;载气高纯氦气;柱压45ｋＰａ;ＥＩ源,全扫描方式,扫描范围30～500ｕ,电子倍增器电压1800Ｖ。1.3　样品来源　　由市场购买两种不同花期的韭菜花,一种为全部开花期的韭菜花(样品Ａ),另一种为部分已结种子的韭菜…     

应用裂解气相色谱对生物质快速裂解反应条件的研究

采用现代化学分析领域中重要的分析方法 -裂解气相色谱法 ,对生物质的快速裂解进行了探索性研究。以杨木木屑为研究对象 ,在裂解温度 40 0～ 80 0℃ ,升温速率 1 0 0℃ s、2 50℃ s、50 0℃ s,挥发性产物停留时间 0 6～4 0s的裂解条件下 ,考察了杨木木屑快速裂解气、液、固三种产物及气相组分的分布规律。实验结果表明 ,气、液、固三种产物所占比例及其组分含量取决于裂解条件 -裂解温度、挥发份停留时间和升温速率 ,杨木在升温速率50 0℃ s、挥发性产物停留时间 0 6s、裂解温度 50 0℃下快速裂解 ,可获得最大的产液率 80 % (含水 )。物料平衡的结果证明了裂解色谱研究方法的有效性和可行性。     

聚甲醛的催化裂解-气相色谱质谱分析

本文利用催化裂解-气相色谱/质谱分析技术(CP-GC/MS),对聚甲醛及共聚甲醛进行链结构分析及裂解机理的探讨。 实验部分 (一)仪器与试样 1.日本岛津PYR-2A型管式炉裂解器,日立633型气相色谱仪,M-80质谱,M-003计算机处理机。2.试样:上溶厂     

沙门氏菌全细胞的热裂解气相色谱-质谱分析

本研究探讨了一种新型的快速检测食源性病原菌的方法。该方法应用热裂解气相色谱-质谱技术(pyrolysis-gas chromatography-mass spectrometry,Py-GC-MS)对食源性致病菌沙门氏菌进行了分析。通过对影响总离子流色谱图条件(热裂解条件、色谱条件、质谱条件)的研究,得到了满意的实验结果。结果表明:沙门氏菌全细胞在裂解温度600℃,时间为10s,离子源温度220℃,电离方式为EI,电离能为60eV的条件下可得到清晰的总离子流色谱图,同时对部分裂解产物的结构进行了鉴定。该方法快速、简便,可为研究快速鉴定致病菌提供新的技术手段。     

PC/ABS共混物的PGC-MS定量分析

采用裂解/气相色谱-质谱联用方法(PGC-MS)对制备的一系列已知配比的PC/ABS共混物进行分析。实验比较了650、750℃裂解温度下共混物的裂解质谱总离子流图,选择PC/ABS共混物的快速鉴定的裂解温度为750℃;通过对已知PC/ABS配比的共混物的特征裂解碎片进行定量分析,发现当共混物中ABS和PC的质量比不大于20∶100时,特征裂解碎片苯乙烯与苯酚的峰面积之比与共混物中ABS/PC的配比呈线性关系,该现象可作为PC/ABS共混物定量分析的依据。     

单扫示波极谱法测定食品中山梨酸

1　引　　言山梨酸 (ＳＡ)是广泛使用的食品防腐剂。已往测定有ＴＬＣ法、比色法、ＧＣ法及ＨＰＬＣ法等。作者研究发现在 0 .2ｍｏｌ/ＬＮＨ4ＡＣ ＨＡＣ(ｐＨ 5 .7)底液中 ,ＳＡ与联氨反应生成酰肼产物并在电位 (Ｅｐ) - 1.2 6Ｖ(ｖｓ·ＳＣＥ)处产生灵敏的还原波 ,其波高与ＳＡ浓度在一定范围内成正比。据此建立了单扫示波极谱法测定食品中ＳＡ的简便分析方法。2　实验部分2 .1　仪器与试剂　ＭＰ 2型溶出分析仪 (山东电讯七厂 ) ,滴汞电极、甘汞电极和铂电极。ＳＡ标准溶液 (国家标样中心研制ＧＢＷ (Ｅ) 10 0 0 0 7) :1.0 0ｇ/Ｌ ;1.0…     

基体辅助激光解吸电离飞行时时质谱和热裂解色谱/质谱研究聚酯型聚氨酯链结构

聚酯型聚氨酯样品用基体辅助激光裂解离子化质谱（ＭＡＬＤＩ－ＴＯＦ／ＭＳ）和热裂解色谱质谱（ＰＹＧＣ／ＭＳ）方法进行了鉴定,ＰＹＧＣ／ＭＳ方法可检出ＰＵ的一些组成单元的化学结构,但ＰＹＧＣＩＭＳ中大多数的峰,无法从常规的标准化合物的质谱数据库中检索到,而ＭＡＬＤＩ－ＭＳ方法,可明确测出ＰＵ试样各种单元的组合、聚合度及ＰＵ长链的序列分布,质量数范围可达2300.     

有机硅橡胶裂解产物气相色谱-质谱联用分析

以室温硅橡胶和高温硅橡胶产品的边角废料及次品作为实验原料,进行到催化和碱催化裂解,将裂解产物进行气相色谱－质谱（ＧＣ－ＭＳ）联用分析,经过质谱数据检索,确定了两种酸催化产物的组成,高温橡胶的酸催化裂解产物主要是环状化物合;室温橡胶的酸催化一妥产物中有太和链状两类化合物,该实验为硅像胶废料利用提供了依据。碱催化产物太复杂,产物利用存在困难。     

Identification of polymer building blocks by Py–GC/MS and MALDI-TOF MS

The main goal of this work is to identify polyurethane (PU) building blocks by pyrolysis gas chromatography/mass spectrometry (Py–GC/MS) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) are widely used polymer building blocks. Py–GC/MS and MALDI-TOF MS were proved to be powerful methods to distinguish TDI-PU and MDI-PU according to the characteristic pyrolysis products and the different repeated units, respectively. In Py–GC/MS, the specific pyrolyzates are TDI for TDI-PU and MDI for MDI-PU. In MALDI-TOF MS, the weights of repeated units are 264?g/mol for TDI-PU and 340?g/mol for MDI-PU.     

Mass spectrometric techniques for characterizing low-molecular-weight resins used as paint varnishes

The molecular structure of three low-molecular-weight resins used as paint varnishes has been characterized by use of an approach based on three different mass spectrometric techniques. We investigated the ketone resin MS2A, the aldehyde resin Laropal A81, and the hydrocarbon resin Regalrez 1094, now commonly used in restoration. To date, the molecular structures of these resins have not been completely elucidated. To improve current knowledge of the chemical composition of these materials, information obtained by gas chromatography–mass spectrometry (GC/MS), pyrolysis–gas chromatography–mass spectrometry (Py/GC/MS), and electrospray ionization mass spectrometry (ESI–Q–ToF) was combined. Analysis, in solution, of the whole polymeric fraction of the resins by flow-injection ESI–Q–ToF, and of the non-polymeric fraction by GC–MS, enabled us to identify previously unreported features of the polymer structures. In addition, the Py–GC/MS profiles that we obtained will help to enhance the databases currently available in the literature. The proposed approach can be extended to other low-molecular-weight resins used as varnishes in conservation.     

Synthesis and characterization of saturated and unsaturated polysulfide polymers and their thermal degradation processes investigated by flash pyrolysis–gas chromatography/mass spectrometry

The synthesis of polysulfide polymers with unsaturated and saturated units in the backbone and their characterization by Fourier transform infrared, NMR, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry are reported. This is the first report on an analysis of the thermal degradation of an unsaturated polysulfide polymer [poly(2‐butene sulfide)] carried out by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). A unique phenomenon of exothermic degradation has been detected by differential thermal analysis and has been attributed to the energetics of the unsaturated polysulfide linkage during degradation. The thermal degradation products studied by Py–GC/MS indicate that the formation of sulfur‐containing products is more favored than the formation of non‐sulfur‐containing products. Furthermore, a comparative study of the thermal degradation of unsaturated and saturated polysulfide polymers has been conducted with thermogravimetry and Py–GC/MS analyses. These analyses have shown that the mechanisms of degradation of these polymers are different, and the lower number of pyrolysis products indicates a selective cleavage of the polymer during degradation in the saturated polysulfide polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 638–649, 2005     

Photochemical degradation study of polyvinyl acetate paints used in artworks by Py–GC/MS

Photochemical degradation of commercial polyvinyl acetate (PVAc) homopolymer and PVAc paints mixed with burnt umber, cobalt blue, cadmium red dark, nickel azo yellow and titanium white commonly used for artworks were studied by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Py–GC/MS with single-shot technique was used for the characterization of the thermal degradation of PVAc at different temperatures, while the double-shot technique of Py–GC/MS was used to reveal the differences in the specimens before and after UV ageing, including the changes of detectable amounts of deacetylation product – acetic acid and plasticizers such as diethyl phthalate (DEP). Furthermore, the relative concentration of the pyrolysis products of the paint samples could be measured and compared in the second step of the double-shot Py–GC/MS, which are highly dependent on the presence of pigments and the ageing status of PVAc paints.     

Differentiation of resin-modified paints by pyrolysis-gas chromatography/mass spectrometry and principal component analysis

The combination of pyrolysis (Py) with gas chromatography/mass spectrometry (GC/MS) is already well established for polymer analysis. A first approach is reported using this method for detailed quality monitoring of a complex technical polymer system. Six similar solvent-based paints (one standard and five modifications) have been used for evaluation. The major pyrolysis products were identified and qualitative and quantitative modifications were detected and specified. Principal component analysis (PCA) was applied for visualization of differences and similarities.     

Differentiation of resin-modified paints by pyrolysis-gas chromatography/mass spectrometry and principal component analysis

The combination of pyrolysis (Py) with gas chromatography/mass spectrometry (GC/MS) is already well established for polymer analysis. A first approach is reported using this method for detailed quality monitoring of a complex technical polymer system. Six similar solvent-based paints (one standard and five modifications) have been used for evaluation. The major pyrolysis products were identified and qualitative and quantitative modifications were detected and specified. Principal component analysis (PCA) was applied for visualization of differences and similarities.     

聚亚苯基苯并二噻唑与聚亚苯基苯并二噁唑的热分解

用高分辨裂解气相色谱 质谱（ＨＲＰｙＧＣ ＭＳ）研究了聚亚苯基苯并二噻唑、聚亚苯基苯并二唑的热分解行为,鉴定了相应裂解产物的组成、分布及其与高分子结构的关系,并用热重法（ＴＧ）测定了它们的热分解反应动力学参数,提出了其热分解反应机理     

Hyphenation of Curie-point-pyrolysis high-resolution gas chromatography with several spectroscopic methods for the analysis of cured epoxy resins

The coupling of Curie-point pyrolysis (Py) with gas chromatography (GC) and mass spectrometry (MS) or Fourier transform infrared spectroscopy (FTIR) has been widely reported. The approach reported in this paper combines chromatographic separation with eluent monitoring by use of three different spectroscopic detectors (MS, FTIR and Atomic Emission Detector [AED]). The features of these detectors, with different selectivities, are shown for the analysis of cured epoxy resins. Besides characterisation of major resin constituents by identification of the pyrolysis products, the usefulness of the AED is also revealed by the detection of minor compounds (such as coupling agents) in cured epoxy resins.     

Characterization of the chemical differences between solvent extracts from Pu-erh tea and Dian Hong black tea by CP–Py–GC/MS

Solvent extracts from a type of Pu-erh tea and Dian Hong black tea were characterized by Curie-point pyrolysis–gas chromatography–mass spectroscopy (CP–Py–GC/MS). The ethyl-acetate extracts from both teas showed similar CP–Py–GC/MS results, with main pyrolytic products of carbon dioxide, caffeine, o-phenols, and phthalate esters. During pyrolysis, the n-butanol extract from Pu-erh tea formed carbon dioxide (38.92% of total pyrolytic products), alkaloids (49.7%), and nitrogen oxides (8.38%), as well as a small fraction of esters. The n-butanol extract from Dian Hong tea formed mainly alcohols, amines, esters, phenols, carboxylic acids, and alkaloids. The raw theabrownin extracts (ethanol precipitates) from the two teas produced substantially different CP–Py–GC/MS results. The raw theabrownin extract from Pu-erh tea formed mostly carbon dioxide during pyrolysis, whereas the counterpart extract from Dian Hong tea formed mainly carbon dioxide (48.23%) and nitrogen oxides (35.39%). The 3.5–100 kDa fractions separated from the theabrownin extracts of the two teas showed similar CP–Py–GC/MS results, whereas the fractions <3.5 kDa and >100 kDa formed substantially different pyrolytic products. These results showed that solvent extracts from Pu-erh tea and Dian Hong tea had substantially different chemical compositions and structures. The study suggested that CP–Py–GC/MS can be used to effectively identify chemical differences between tea extracts.     

Rapid methods of polymer and polymer additives identification: Multi-sample solvent-free MALDI, pyrolysis at atmospheric pressure, and atmospheric solids analysis probe mass spectrometry

Polymer manufacturers add antioxidants, waxes, dyes, and other materials to enhance polymer utility or processing. Numerous analytical methods are available to characterize various chemical aspects of polymers including methods interfaced with mass spectrometry (MS) such as pyrolysis (Py), gas chromatography (GC), liquid chromatography (LC), and thermogravimetric analysis (TGA). Current methods work well, but because of the necessity of extraction, chromatography, or thermal methods, most are too time consuming for high throughput analyses which might be necessary in, for example, regulatory laboratories. Here we discuss three MS methods for rapid analysis of polymers; multi-sample MALDI MS which allows rapid analysis of low molecular weight polymers, atmospheric pressure (AP) solids analysis probe MS for direct ambient additives analysis, and APPy MS for polymer identification. The latter methods provide information regardless of the composition or molecular weight of the polymeric material.