Identification of phenyl-substituted polycyclic aromatic compounds in ring furnace gases using GC-MS and GC-AED

Summary The ring furnace baking process is an intermediate step in the production of graphite electrodes. In this process coal tar pitch is pyrolized to form amorphous carbon and volatile aromatic and polycyclic aromatic compounds (PACs). These gaseous ring furnace emissions were analysed by GC-MS and GC-AED. As a result of the pyrolytic reactions taking place, several phenyl-substituted PACs are generated, which were identified by their chromatographic retention indices and mass spectra. Pure reference compounds were analysed for verification if available. A number of phenyl-PACs are reported to be present in coal tar-related material, including phenylpyridines and phenyldibenzofurans previously unreported. A formation scheme for phenyl-dibenzofurans on the basis of a radical mechanism is proposed. Dedicated to Prof. Dr. Wolfgang Meyer zu Reckendorf, Münster, on the occasion of his 65th birthday. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Identification of chlorinated sulfur compounds in pulp mill effluents by GC-MS and GC-AED

Summary Three chlorinated dimethyl sulfones and five chlorinated thiophenes have been identified in the alkaline extraction liquor from a bleach plant by gas chromatography with atomic emission detection (GC-AED) and with mass spectrometry (GC-MS). The information on elemental content obtained by GC-AED enabled a rapid screening of the sulfur compounds and provided important structural information complementary to the mass spectral data. Quantitation was accomplished by GC-AED based on universal calibration.     

Fast analysis of oxygen and sulfur compounds in gasoline by GC-AED

This paper describes a method for determining both the total sulfur content and the concentration of oxygenated additives in gasoline by gas chromatography with atomic emission detection (GC-AED). The AED provides selective detection of oxygen and sulfur compounds. Because the response factors for sulfur and oxygen are largely independent of the type of compound, calibration and determination of total element content are simplified. The use of a 0.1 mm i.d. capillary column enables complete elution of the components of the gasoline in under 10 minutes.     

On the complementary nature of CGC-MS,CGC-FTIR,and CGC-AED for water pollution control

Unequivocal identification of unknown pollutants is very difficult if only one dimension of information is used. Combining different hyphenated techniques can, on the other hand, lead to more reliable identification. Combination of the data provided by the different techniques is more important than on-line combination of the techniques themselves.     

傅立叶变换红外光谱法在高聚物分析中的进展

本文综述了漫反射傅立叶变换红外光谱法，傅立叶谱换红外光声光谱法，显微傅立叶变换红外光谱法，傅立叶变换红外光谱仪与各种仪器的联用，以及计算机技术等在高聚物分析中的应用。     

Compositional studies of high-temperature coal tar by GC/FTIR analysis of light oil fractions

Summary A method for determination of the composition of the light oil fractions in high-temperature coal tar by means of distillation, followed by gas chromatography on a crosslinked fused-silica, capillary column coated with optimum amount of stationary phase and identification by capillary gas chromatography/Fourier transform infrared spectrometry combined with GC retention indices (GC/FTIR-RI) is described. This method was effectively used to identify complex mixture such as coal tar without any standard samples, especially, adapted for isomeric compounds. More than 60 and 50 compounds were also separated and identified respectively in light oil fractions. This shows the capability of the capillary GC/FTIR combined with GC retention indices to identify isomers not accomplished by GC/MS.     

Direct probe CI-MS and APCI-MS for direct materials analysis

Direct probe in vacuo chemical ionization (isobutane CI-MS) and Pyroprobe atmospheric pressure chemical ionization (APCI-MS) are complementary techniques for the analysis of polymeric materials. Both techniques can generally be used to detect residual chemicals and more volatile additives (via thermal desorption), as well as polymeric components (via pyrolysis).Isobutane CI-MS is often a “softer” technique than APCI-MS, giving less background, less fragmentation, and more predictable and reproducible spectra. APCI, on the other hand, provides a higher maximum temperature and a means to carry out sample heating at atmospheric pressure (to simulate TGA). Pyroprobe APCI with high performance instruments has the added features of high resolution mass measurement (to determine atomic compositions) and tandem mass spectrometry (MS/MS, to obtain fragmentation patterns).     

A fatty acid methyl ester (FAMES) analyzer

Fatty acids, as their methyl esters (FAMES), are routinely analyzed from a wide variety of plant and animal tissues and fluids. Samples have mainly been analyzed to date using capillary GC with FID detection. However, FID detection is non-specific, and open to misinterpretation. This is particularly important in the analysis of minor lipid components from, e.g. organ tissues, plasma and other body fluids, where non-FAMES impurities or contaminants can be present in relatively high amounts. This suggests that even for routine work, a mass spectral detector is necessary for the unambiguous identification–or rather, recognition–of FAMES. The FAMES analyzer we propose consists of three components: an automatic injector; a medium polarity, high-temperature stable capillary column; a mass spectrometric detector, in our case the Finnigan–MAT ion trap detector (ITD 800). Here, on-column injection allowed controlled sample transfer even for low absolute concentrations of lipids, and a column effluent splitter gave simultaneous qualititative and quantitative analysis. For automatic routine analysis, a mass spectral library routine using a tailor-made library of FAMES spectra of the most common naturally occurring fatty acids, plays an essential role. Library comparison parameters used in the standard ITD software usually give “first hit” recognition over a wide sample dynamic range (ca. 2 pg to > 200 ng in the best cases). This gives an absolute recognition even of minor lipid components, especially when combined information from mass spectra and GC retention data is used. By analogy with the now well known concept of the Amino Acid Analyzer, we propose the system described as a FAMES Analyzer. Mass spectrometers like the Finnigan MAT ITD 800 are inexpensive, reliable, sensitive, and easy to operate. Unlike the Amino Acid Analyzer, the FAMES Analyzer needs the specific detection offered by mass spectrometry because the number of acids to be analyzed, including isomers, is much greater.     

Automated screening of food and water samples for pesticide residues by means of capillary GC-MSD using a library of pesticide spectra and macro programming

Automatic pesticide screening has been performed by use of a macro program to compare mass spectra acquired during GC-MS with those in designated mass spectral libraries containing a limited number of target compounds. The automated evaluation procedure has enabled fast recognition of pesticides in complex chromatograms.     

Simultaneous determination of organotin,organolead, and organomercury compounds in environmental samples using capillary gas chromatography with atomic emission detection

As part of a continuing evaluation of new analytical and sample preparation techniques conducted by the US Environmental Protection Agency (EPA), the use of capillary gas chromatography with atomic emission detection (GC-AED) for the simultaneous determination of organotin, organolead, and organomercury compounds in environmental samples was investigated. Pentylmagnesium bromide was used to pentylate ionic organotin, organolead, and organomercury compounds; the pentyl derivatives were then separated by GC and determined by AED. Several important GC-AED parameters, including the type of injector inlet, carrier gas flow rate, and helium make-up gas flow rate, were optimized for the simultaneous determination of these organometallic compounds. Their minimum detectable concentrations were approximately 1.0 to 2.5 ng/mL using a 0.5-μL on-column injection. The calibration curves exhibited good linearity between 2.5 and 2500 ng/mL for organotin and organolead compounds, and between 2.5 and 10000 ng/mL for organomercury compounds.     

Rapid analysis of hydrocarbons and inert gases by a multidimensional gas chromatograph

A combination of a pressure switching system with multiple columns and photoionization detectors makes possible rapid analysis of a mixture of inorganic gases and hydrocarbons. Hydrocarbons are separated by a narrow bore capillary column. An alumina PLOT column is used for the separation of lower molecular weight hydrocarbons, especially C4 isomers, while a combination of a micro-packed column with Porapak N and a PLOT capillary column with Molecular Sieve 5A is used for the fast separation of inorganic gases. A photoionization detector is a powerful additional tool for organic gas analysis.     

Combined system and its application of thermogravimetric analysis/FT-IR

A TGA/FT-IR system and its application is described. The gases evolved from TGA were induced to the temperature controlled flow cell of an FT-IR spectrophotometer through the temperature controlled transfer pipe and were measured by FT-IR spectrophotometer. The results from the analysis of ethylene-vinyl-acetate copolymer and water-soluble paint are shown.     

A REVIEW OF HYPHENATED CHROMATOGRAPHIC INSTRUMENTATION

Samples presented for chemical analysis are invariably mixtures, often very complex mixtures. This has led to the widespread acceptance and application of what have become called hyphenated chromatographic techniques. These techniques are combinations of chromatographic instrumentation with some (usually) spectroscopic technique. In this review, we treat the most important and useful of these combinations. The basic instrumental features of each method are described, and possible applications are discussed. The relative capabilities of each technique are weighed, and tradeoffs are discussed. In closing, a list of suggested further reading is provided.     

Optimization of capillary SFC-MS for the determination of additives in polymers

A standard direct introduction capillary interface is used for the SFC-MS analysis of polymer additives. The system is optimized with respect to the position of the restrictor, probe tip temperature, and ion source temperature. El-like charge-exchange spectra are obtained. Cl using ammonia as the reagent gas is used for the quantitative analysis of a real world sample. The experimental capillary SFC-MS spectra obtained show a good similarity with those recorded using the direct insertion probe. The influence of the experimental conditions on the mass spectra obtained is evaluated statistically.     

A unified approach to the chromatography/FT-IR interface

Most previous interfaces between a Chromatograph and an FT-IR spectrometer have been applicable to only one type of chromatograph-gas, liquid, or supercritical fluid. In this paper, the similarities and differences between various chromatography/FT-IR interfaces are described, and an interface which should be equally applicable to all three types of chromatography is proposed. In each case, the mobile phase is eliminated while the eluting components are condensed in a small area on a moving substrate. The spectra are then measured using an FT-IR microscope. The methods by which the mobile phase is eliminated depend on the nature of the chromatography, while the infrared sampling technique is determined by the nature of the substrate. The relative merits of transmission, reflection-absorption, diffuse reflection, and diffuse transmission spectrometry are discussed.     

Determination and distribution of polycyclic aromatic hydrocarbons in native vegetable oils,smoked fish products,mussels and oysters,and bream from the river Elbe

Twenty eight native vegetable oils were analyzed for polycyclic aromatic hydrocarbons. Generally PAH concentrations were low, but olive oils showed significantly higher contamination by light PAH ranging from 53 to 105.6 μg/kg. Muscle and liver samples of bream from the river Elbe contained little or no detectable amounts of PAH, whereas fresh and canned oysters and mussels showed higher contaminations. Highest PAH concentrations have been determined in “smoked oysters in oil” with 75.8 μg/kg benzo[a] pyrene for the oil and 12.2 μg/kg for the oyster meat.     

Polymer crystallinity studied using Raman spectroscopy

The application of Raman spectroscopy to the study of crystallinity in polymers has been examined. In particular, Fourier transform (FT)-Raman spectroscopy has been applied in a number of studies in recent years to investigate crystallinity in a variety of polymers. The polymers discussed in this review are polyethylene, polystyrene, poly(ether ether ketone), polyamides, poly(ethylene terephthalate), elastomers, liquid crystalline polymers, inorganic polymers and certain polymer blends.