Pyrolysis-capillary gas chromatography-mass spectrometry for the determination of polyvinyl chloride traces in solid environmental samples

A novel method based on pyrolysis-capillary gas chromatography-mass spectrometry (CGC-MS) was developed for the quantitative analysis of polyvinylchloride (PVC) in solid environmental samples like sludge and dust. The samples are extracted and the extract is fractionated by solid-phase extraction (SPE). Possibly interfering biological and frequently occuring synthetic polymers are removed by this clean-up. The final extract is analyzed by pyrolysis-CGC-MS. Selective detection of PVC is performed by using specific markers in the pyrogram. Quantitation is done on naphthalene. Good linearity was obtained in a range from 0.5 to 100 microg applied to the pyrolyser. The limit of quantitation (LOQ) in sludge and dust samples is 10 mg/kg dry mass. A correlation between PVC and phthalates was made for sewage sludge samples.     

Qualitative analysis of dental resin composites by gas and liquid chromatography/mass spectrometry

Ten different composites used in dentistry for cavity filling, cementation and sealing were analyzed by gas chromatography/ mass spectrometry and liquid chromatography/mass spectrometry using a particle beam interface and direct ionisation mass spectrometry. In this way monomers and various additives as well as contaminants from manufacturing processes could be identified, including compounds which should be avoided from a toxicological point of view.     

Fast gas chromatography: packed column solvating gas chromatography versus open tubular column gas chromatography

Packed capillary column solvating gas chromatography (SGC) and open tubular column gas chromatography (GC) were compared with respect to their potentials for fast separations. A recently introduced "universal" peak capacity equation was used to compare the performance of these two methods. The effects of various factors on peak capacity were investigated. Results demonstrate that retention factor and column efficiency are the main factors affecting peak capacity for fast separations. Packed columns produce both high retention factors and high selectivities. While high efficiencies and high peak capacities can be demonstrated by both techniques, open tubular column GC can surpass packed capillary column SGC in both measurements, except for the case of the analysis of simple mixtures in short analysis times, where retention factor and selectivity become important. Practical aspects such as pressure drop and sample capacity are compared for SGC and open tubular column GC. It was found that packed column SGC demonstrates higher sample capacities, but requires much higher column inlet pressures than open tubular column GC. A variety of mobile phases can be used for packed column SGC, which can provide high solvating power for large and polar compounds.     

Inorganic gas chromatography

Summary The possibilities of using gas-solid chromatography as a method for the separation of trace amounts of various elements such as volatile chlorides or oxychlorides are investigated. The use of quartz as the column material and graphite, quartz or quartz coated with different ionic chlorides of low volatility as the stationary phase allows the use of temperatures up to 1100 K and consequently the separation of many elements as chlorides. The theory of linear equilibrium chromatography is applied successfully to the investigation of the influence of temperature and the type of solid (stationary) phase, in order to optimize separations. The dependence of the peak width on the various parameters is more complex, but several general principles can be derived from the experimental results. From these data physicochemical properties of the adsorbate-adsorbent systems investigated can be derived, and the optimum conditions for isothermal separations can be estimated.     

History of gas chromatography

Modern gas chromatography (GC) was invented by Martin and James in 1952 [1], and has become one of the most important and widely applied analytical techniques in modern chemistry. Major milestones in the development of GC, especially in column technology, detection and sample introduction are described in this historical review. Many trends in current progress can be seen to originate in the first two decades of the history of GC, but the invention of fused-silica capillary columns greatly increased the application of high-resolution GC across the field of organic analysis; the development of low-cost, bench-top mass spectrometers led to further advances. Progress continues to be rapid in comprehensive 2D GC, fast analysis, detection by atomic emission and time-of-flight mass spectrometry, and in applications to process analysis.     

Capillary reaction gas chromatography

Summary Thermal decomposition of C₆ hydrocarbons (hexane, cyclohexane, 2-methylpentane, 2,2-dimethylbutane and trans-2-hexene) on a nickel catalyst and on alumina was studied by reaction gas chromatography. The products were analyzed on two capillary columns containing squalane and Citroflex and were identified on the basis of their retention indices. The degree of conversion of the initial substances and the relative contents of the products were determined. On the basis of the results obtained, the probable course of the catalytic decomposition is discussed.     

气相色谱近年的发展

简要阐述了近几年气相色谱(GC)的发展和特点。GC是一个成熟的技术,广泛地应用于各个领域,近几年GC的发展除了继续研究新的固定相和高性能的毛细管色谱柱之外,主要在全二维气相色谱(GC×GC)、快速GC、便携式GC仪和微型GC仪几个方面。近几年新研究的GC固定相主要集中在常温离子液体和各种环糊精的衍生物。现在GC研究者趋向于使用商品化的GC毛细管柱,而商品化的GC毛细管柱应用最多的是以含5%苯基的聚甲基硅氧烷为固定相的色谱柱。GC×GC发展迅猛,特别是关于调制器的研究,已开发出十多种调制模式,并广泛地应用于各个领域。为了适应大量样品的分析和现场分析,研究和开发了多种快速GC方法和仪器以及便携式GC仪。为了仪器的小型化和专属性检测,μGC仪的研究也稳步地发展起来。