Physical and chemical characterization of petroleum products by GC-MS

There is a need for reliable and fast means of monitoring refining, conversion, and upgrading processes aiming to increase the yield of light distillates, and thus, reducing the oil barrel bottoms. By simultaneously utilizing the FID and mass selective detectors while splitting the column effluent in a controlled way, it is possible to obtain identical gas chromatograms and total ion chromatograms from a single run. This means that besides the intensity vs. time graphs, the intensity vs. mass and boiling point can also be obtained. As a result, physical and chemical characterization can be performed in a simple and rapid manner. Experimental results on middle, heavy distillates, and crude oil fractions show clearly the effect of upgrading processes on the chemical composition and yields of diesel, jet fuels, and high vacuum gasoil fractions. The methodology is fully compliant with ASTM D-2887, D-7213, D-6352, and D7169 for simulated distillation and the previously mentioned mass spectrometry standards. The group type analysis correlated satisfactorily with high-performance liquid chromatography data.     

裂解气相色谱-质谱联用技术研究黑香豆酊的热裂解行为

采用裂解气相色谱-质谱联用法研究了香精黑香豆酊在不同温度下的裂解行为,分析了黑香豆酊在不同温度下的热裂解产物,并用归一化法进行了定量。结果发现黑香豆酊在不同温度下表现出不同的转移行为,其热解产物和机理也各不相同。检索到苯并呋喃、香豆素和肉桂醛等16种致香物质。随着温度的升高,裂解产物中逐渐产生出有害物质。初步探讨了香豆素可能的裂解机理,为香味物质在卷烟燃烧过程的转化行为提供了例证。     

对环芳烷二氯化产物组成的GC-MS表征

对环芳烷([2,2]Paracyclophane,简称PCP）是指苯环对位桥联的化合物,PCP及其氯代PCP的重要用途是通过升华、裂解、聚合等步骤沉积于物体表面形成聚合膜,该聚合膜具有透湿和透气小、抗化学腐蚀和抗辐射等优良性能[1,2].     

GC-MS characterization and quantification of sterols and cholesterol oxidation products

Summary A GC-MS method has been studied for characterization and quantification of phytosterols, cholesterol and cholesterol oxidation products. Baseline separations have been achieved between cholesterol, cholesterol 5-6-epoxide, 5-cholestene-3-ol-7one (7-keto-cholesterol), cholestene-3-5-6-triol, 5-cholestene-3-25-diol (25-hydroxycholesterol), 5-cholestene-3-20-diol (20-hydroxycholesterol), 5-cholestene-3-7-diol (7-hydroxycholesterol) and 5-cholestene-3-19-diol (19-hydroxycholesterol) as well as between -cholestane, cholesterol, stigmasterol, campesterol and -sitosterol. Excellent linearity of response has been obtained permitting reliable quantification. The characterization of each derivatized sterol has been performed by mass-spectrometry. The results confirm the utility of combined gas chromatography-mass spectrometry in the analysis and characterization of sterols and cholesterol oxidation products.     

Determination of limonene oxidation products using SPME and GC-MS

Limonene is a common component found in consumer goods ranging from beverages to cleaning compounds. Limonene oxidation products, however, have a less desirable flavor and fragrance. Early detection of limonene oxide formation would aid quality control. A method is developed to determine the concentration of limonene oxide in essential oils and beverages using solid-phase microextraction (SPME). A headspace sampling technique is used to reduce or eliminate the presence of less volatile components. Several different SPME fibers are tested, varying in polymer thickness, polymer cross-linking and bonding, and polarity of the polymer. For each fiber tested, the sampling time is optimized for reproducible results. The 7-microm-thick bonded poly(dimethylsiloxane) fiber provides the best results. External standards are used for quantitation.     

气相色谱-质谱法测定电子电气产品塑料部件中有机锡

气相色谱-质谱法(GC-MS)测定电子电气产品塑料部件中一甲基锡(MMT)、二甲基锡(DMT)、一丁基锡(MBT)、二丁基锡(DBT)、三丁基锡(TBT)、一辛基锡(MOT)、二辛基锡(DOT)、三辛基锡(TOT)、三苯基锡(TPhT)。溶解于四氢呋喃的样品经四乙基硼酸钠水溶液衍生、沉淀后,以GC-MS定性定量检测。方法平均回收率为85.9%～107.2%,RSD低于10%。在9个电子电气产品塑料部件样品中,2个样品检出含有0.050%～0.212%的MMT及DMT,GC-MS与ICP-AES方法测得总锡含量分别为0.21%、0.18%,方法间无显著差异。     

Thermochemical conversion of coconut waste: material characterization and identification of pyrolysis products

Journal of Thermal Analysis and Calorimetry - In this work, coconut waste was evaluated for its potential for biofuel production via pyrolysis by considering physicochemical properties, kinetics of...     

氟草烟残留的GC-MS法测定研究

采用气相色谱-质谱联用法测定蔬菜、水果中的氟草烟,即用乙腈提取样品后,将提取液用氮气吹干,加入甲醇、浓H2SO4酯化。酯化物中加入10mL20g/LNa2SO4溶液,5mL正己烷充分混匀。取正己烷相进GC-MS。氟草烟的检出限为:1.40×10-3μg/g。     

Application of pyrolysis - GC and pyrolysis - GC-MS to fossil fuel research

Pyrolysis - gas chromatography (py-GC) and pyrolysis-gas chromatography - mass spectrometry (py-GC-MS) are used increasingly in fossil fuel research. These techniques can be employed to determine the source and maturity of organic matter in coals, oil shales and oil source rocks and to identify liquefaction products from coal and oil shales.     

Determination of chlorinated paraffins by GC-MS

Summary Although chlorinated paraffins are widely used and therefore produced in large amounts (about 250 kt/a) — with well known problems —, there is a lack of a selective, highly sensitive and reproducible analytical method for the determination of these substances. Such a method is presented using GC/MS with electron impact ionization for their quantitative determination. The samples, pretreated with conc. sulphuric acid, were cleaned up by solid-phase extraction on alumina, and the chlorinated paraffins were determined by GC/MS using highly selective ion clusters.By this method, determination limits of 3 ng (corresponding to about 1.5 ppb) were routinely obtained. In contrast to the general methods of maximum signal selection or the selection of molecule ions in mass spectroscopy, the presented approach leads to higher selectivity, less discrimination between different types of chlorinated paraffins and allows to obtain further information on the degree of chlorination.     

超声提取-气相色谱/质谱法测定皮革及纺织品中18种多环芳烃

采用超声波萃取技术对样品进行提取,气相色谱联用质谱(GC-MS)选择离子监测(SIM)模式采集数据,建立了皮革及纺织品中18种多环芳烃(PAHs)的分析方法.对色谱、质谱分析条件以及样品前处理条件进行研究与优化.在最优条件下,18种PAHs浓度在一定范围内与其峰面积呈现良好的线性关系,相关系数(R2)为0.9991～0...     

Determination of nitrogen mustard hydrolysis products in rat urine samples using GC-MS

A gas chromatographic-mass spectrometric method was developed, validated and demonstrated by measuring the levels of nitrogen mustard hydrolysis products in the urine collected from dosed rats. The recovery values for trimethylsilyl derivatives of EDEA and MDEA are between 82-95% and 88-112%, respectively. In vivo studies performed by using three different doses (0.5 mg/kg, 1.0 mg/kg, and 2.0 mg/kg) of HN2 base of nitrogen mustard. MDEA concentrations were between 43.1-232.2 ng/mL. The limit of detection (S/N = 3) values are 2.5 ng/mL and 1.6 ng/mL for EDEA and MDEA, respectively, and the precision of the method in terms of RSD is between 5-8%.     

气相色谱–质谱联用法测定空气中的丙烯腈

建立测定空气中丙烯腈的气相色谱–质谱联用方法。用活性炭管采集样品,以体积分数为2%的丙酮二硫化碳溶液解吸,利用气相色谱–质谱法以选择离子扫描方式采集数据并进行分析,以色谱峰面积外标法定量。丙烯腈的质量浓度在0~100μg/m L范围内与色谱峰面积线性关系良好,线性相关系数(r~2)为0.999 0。丙烯腈检出限为1.2μg/m L,最低检出质量浓度为0.16 mg/m~3(以采样体积7.5 L计),平均加标回收率为97.0%~99.3%,测定结果的相对标准偏差为3.0%~4.2%(n=6)。该方法定性、定量准确,精密度、灵敏度高,可用于空气中丙烯腈的常规检测。     

气相色谱-质谱法测定化妆品中的氯霉素

氯霉素是一种广谱抗生素,化妆品卫生规范规定氯霉素等抗生素为禁用物质。关于氯霉素的检测多采用高效液相色谱（HPLC）和高效液相色谱-质谱（HPLC-MS）测定,或者经N,O-双三甲摹硅烷基-三氟乙酰胺（BSTFA）、三甲基氯硅烷（TMCS）等硅烷化后进行气相色谱（GC）、GC-MS测定。本文建立了采用较为普通的乙酸酐试剂进行衍牛化,然后用GC-MS测定的方法。将该法应用于化妆品中氯霉素的检测,取得了较好的效果。     

气相色谱-质谱法测定大豆中的豆磺隆的残留量

建立了气相色谱-质谱法测定磺酰脲类除草剂豆磺隆在土壤中的残留量方法,利用豆磺隆的热不稳定性,对其水解产物4-氯-6-甲氧基嘧啶胺进行选择离子测定,定性、定量准确,排除了大豆中复杂基质的干扰,方法的线性、回收率、精密度和检出限均符合残留分析的要求。     

茶叶中有机氯农药的质谱确证分析

中国曾大量使用过以DDT和六六六为代表的有机氯农药,近年来,在对茶叶的检测中已很少检测到六六六,但仍经常检出DDT,甚至DDT超标的现象时有出现。本文建立了分析茶叶中DDT的GC-MS-TIC和GC-MS-SIM方法。目前国内实验室仍多采用GC／ECD分析茶叶中的DDT,本文不仅对使用GC／ECD检出的DDT进行了GC-MS确证分析,而且对GC／ECD分析茶叶中DDT的可靠性进行了初步探讨。     

Identification of the phenothiazines by gas chromatography of their pyrolysis products

Summary Nineteen phenothiazines were pyrolyzed and their products analyzed gas chromatographically. The pyrolysis products were compared with those obtained from a similar study of the barbiturates. Tentative identifications have been made of three pyrolysis products. The pyrolyzates of the various phenothiazine derivatives yield gas chromatographie patterns which differentiate among them.

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Zusammenfassung Die Pyrolyseprodukte von 19 Phenothiazinen wurden gaschromato-graphisch analysiert und mit jenen verglichen, die bei einer analogen Untersuchung von Barbituraten erhalten worden waren. Die Identifizierung von drei Pyrolyseprodukten wurde versucht. Die Pyrolysate der verschiedenen Phenothiazinderivate lassen sich gaschromatographisch unterscheiden.

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Résumé On a effectué la pyrolyse de dix-neuf phénothiazines et analysé les produits résultants par chromatographie en phase gazeuse. On a comparé les résultats — ceux obtenus au cours d'une étude semblable sur les barbiturates. On a tenté d'identifier trois produits de pyrolyse. Les produits de pyrolyse de plusieurs dérivé de la phénothiazine donnent en chromatographie en phase gazeuse des enregistrements qui permettent de les différencier.

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Dedicated to Prof.A. A. Benedetti- Pichler on the occasion of his 70th birthday.     

气色相谱-质谱法测定化妆品中的氯霉素

氯霉素是一种广谱抗生素,化妆品卫生规范规定氯霉素等抗生素为禁用物质.关于氯霉素的检测多采用高效液相色谱(HPLC)[1]和高效液相色谱-质谱(HPLC-MS)[2] 测定,或者经N,O-双三甲基硅烷基-三氟乙酰胺(BSTFA)、三甲基氯硅烷(TMCS)等硅烷化[3-4]后进行气相色谱(GC)、GC-MS测定.本文建立了采用较为普通的乙酸酐试剂进行衍生化,然后用GC-MS测定的方法.将该法应用于化妆品中氯霉素的检测,取得了较好的效果.     

Chlorinated products of plastic pyrolysis

The formation of various chlorinated products in pyrolysis of polymers and plastics additives was studied. Formation of chlorobenzenes (in addition to the monomers) from poly(chlorostyrene) and poly(vinylbenzyl chloride) was observed. Hydrogen chloride is only produced from these polymers at above 600 °C when the chlorine atoms are cleaved off and abstract hydrogen. A similar process takes place in aromatic chlorine-containing dyes, in which the strong aromatic molecular structure prevents the thermal cleavage of chloroaromatic volatile products. We have observed that cupric and ferric chlorides chlorinate phenolic thermal decomposition products of plastic materials which originate either from the polymer or from the stabilizer. The highest yields of chlorophenols are obtained in pyrolysis at around 700 °C.