Gas chromatography-coupled mass spectrometry

Several papers utilizing 3 mm probe capabilities were also published that delved into the area of protein structures. Hepatocyte nuclear factor 4 was studied by a group lead by Williams.155 It is interesting to note that a 2.7 A X-ray study showed a fatty acid in the pocket of HNF4y. Gas chromatography coupled mass spectrometry (GC/MS) and 3 mm NMR studies of extracts from purified HNF4x led to the identification of mixtures of saturated and crs-monounsaturated Ci4 to Qg fatty acids. Bertini and co-workers156 utilized 3 mm probe capabilities in the determination of the solution structure of CopC, a cupredoxin-like protein involved in copper homeostasis. 

While the first coupling of gas chromatography and mass spectrometry had been reported in the late fifties [4] one had to wait for almost another 20 years before the direct interfacing of liquid chromatography with mass spectrometry (LC-MS) was described by Arpino et al. [5]. With the direct liquid interface (DLI) the effluent of the chromatographic column was directly introduced in the electron impact source. Contrarily to gas chromatography coupled to mass spectrometry (GC-MS), LC-MS did do not catch on as rapidly. One of the reasons was that the MS interface could only handle LC fiow rates of a few microliters per minute. Another limitation was that electron impact or chemical ionization was not suit-... 

Isotope Abundances Negative Ions Synthetic Models V. High-Resolution Studies VI. Metastable-Ion Techniques VII. Coupled Gas Chromatography and Mass Spectrometry Inorganic and Organometallic Compounds VIII. Conclusion. ... 

VII. Coupled Gas Chromatography and Mass Spectrometry Applied to Inorganic and Organometallic Compounds... 

Excellent separation of sulfonamides can be achieved on conventional or fused silica capillary columns, the preferred type been the DB-5 capillary column. Following separation, electron-capture detector (254, 271) can be used for the determination of these drugs with good sensitivity and specificity. To confirm the presence of sulfonamides residues in edible animal products, mass spectrometric detectors are also frequently employed. Typical examples of such applications are those coupling gas chromatography with mass spectrometry via a chemical ionization (224, 254, 271) or electron impact (223, 256, 261) interface. 

Lamouroux, C., Virelizier, H., Moulin, C., Jankowski, C.K. 2001. Application of gas chromatography-tandem mass spectrometry to the analysis of inhibition of dimerisa-tion of tributylphosphate under radiolysis. Identification of isomeric tributylphosphate-alkylbenzene inhibitor coupling products. J. Chromatogr. A 917 261-275. 

Several papers in this book and in the recent literature (3) discuss use of pyrolysis techniques coupled with gas chromatography and mass spectrometry to determine forms of organically bound sulfur, but these methods introduce an uncertainty due to the possible interconversion of these sulfur forms during the heating step. For example, it has been shown that when benzyl sulfide was heated to 290°C, tetraphenyl thiophene, hydrogen sulfide and stilbene were produced (4). Coupled with heat and mass transport limitation considerations, particularly for viscous liquids and solids, it is not unreasonable to question whether at least some of the thiophenic forms observed by these techniques were produced during the analysis and may not have been present in the original sample. 

HO) Kaiser, R. Problems of coupling of gas chromatography with mass spectrometry in the level of low concentrations. Z. Anal. Chem. 252, 119 (1970). 

The behavioural responses of adult female western flower thrips, Frankliniella occidentalis, to volatiles from meadowsweet (Filipendula ulmaria), bay laurel and sage (Salvia officinalis) were investigated in laboratory bioassays by Chermenskaya et al. (2001). Volatiles collected by entrainment of a solvent extract of F. ulmaria were more attractive than was the original extract. F. occidentalis also was attracted significantly to volatiles from L. nobilis and S. officinalis. Analysis by gas chromatography and mass spectrometry identified 1,8-cineole (euca-lyptol) as one of the main volatile components of all three plant species. In coupled... 

Analysis was carried out by a combination of gas chromatography and mass spectrometry using a Poropak QS (50-80 mesh) column (length 2,2 m. 3,5 mm o.d.) coupled to a Spectramass Selector quadrupole mass spectrometer. 

Studies on the chemical structure of olive wax esters have shown that the homologues present in olive-pomace oil are almost entirely esters of oleic acid with long chain alkanol constituting the homologous series C40, C42, C44, C46. Odd-chain esters identified in the oil were esters of oleic acid with C23, C25, C27 alcohols. Gas chromatography and mass spectrometry analysis has shown that each carbon chain of the esters in made up of a single isomer in which the acyl moiety is that of oleic acid (Bianchi el al., 1994). Thus, for example, ester C44 was found to be made up of the couple acid-alcohol Cl8 1 and C26, whereas other possible isomers such as C16 l-C28 were not detected. This is unusual if it is compared with the composition of epicuticular ester fractions of oil seeds for which, in cases studied, each ester chain was composed of several positional isomers of the ester group. 

Vreuls J J, De Jong GG, Brinkman U. 1991. On-line coupling of liquid chromatography capillary gas chromatography and mass spectrometry for the determination and identification of polycyclic aromatic hydrocarbons in vegetable oils. Chromatographia 31(3-4)113-122. 

Baffin, G. and Grenier-Loustalot, M.-F. (2004) Coupling thermogravimetry with cold trap/gas chromatography and mass spectrometry. Spectra Analyse, 33 (241), 36-43. 

Gas chromatography, GC mass spectrometry, MS hydride generation, HG atomic absorption spectrometry, AAS inductively coupled plasma, ICP solid phase microextraction, SPME fluorine-induced chemiluminescence, FIG. 

On-line coupling of pyrolysis, gas chromatography, and mass spectrometry is a quick and elegant method for the qualitative detection of monomer units in many resins (e.g., polyesters, polyurethanes, phenolic resins, and polyacrylates). Identification of comonomers of polyacrylates, including hydroxy-functional and carboxy-functional monomers, is facilitated if the sample is silylated before pyrolysis [10.30]. 

Figure 1.2 Overview of the EPA s organics protocol. VOCs, volatile organics SVOCs, semivolatile organics OCs/PCBs, organochlorine pesticides/poly-chlorinated biphenyls HS-GC-FID, static headspace coupled to gas chromatography and flame ionization detection LLE, liquid-liquid extraction LSE, liquid-solvent extraction or solvent leaching from solid matrices GC-ECD, gas chromatography and electron-capture detection GC-MS, gas chromatography and mass spectrometry RP-SPE, reversed-phase solid-phase extraction.

Interfaces for Coupling Gas Chromatography with Mass Spectrometry... 

Kaiser, R.E. Thin-layer chromatography in direct coupling with gas chromatography and mass spectrometry. Chem. Britain 1969, 5, 54. 

Brunetto, M. R., Y. Delgado, S. Clavijo et al. 2010. In-syringe-assisted dispersive liquid-liquid microextraction coupled to gas chromatography with mass spectrometry for the determination of six phthalates in water samples. J. Sep. Sci. 33 1779-1786. 

Thermogravimetric analysis coupled with gas chromatography and mass spectrometry has been used to study the nature of the volatiles produced during the curing of epoxy resins. ... 

Wampler and Levy [45] and Chien and Kiang [44] coupled TGA with gas chromatography (GC)-mass spectrometry (MS) to identify volatile oxidation products produced upon heating PP in air. 

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