Mass spectrometry GC/MS gas chromatography with

An experimental study has been carried out with peat samples from the forest area of Brunei Darussalam. We should note here that the measurement of emission products requires comprehensive analytical equipment. Hydrocarbons (C1-C4) are determined by gas chromatography with flame ionization detection (GC/FID), CO2 and O2 are analyzed by gas chromatography with thermal conductivity detection (GC/TCD), and CO, by gas chromatography with electron capture detection (GC/ECD). Aldehydes and polynuclear aromatic hydrocarbons (PAHs) are determined by gas chromatography with mass spectrometry (GC/MS). 

Gas chromatography with mass spectrometry (GC-MS) (a) Detection of the presence of cocaine metabolites (breakdown products) in hair (b) Identification of strychnine in blood. 

For most volatile or gaseous species more selectivity may be achieved by combining mass spectrometry with gas chromatography. This is applicable to some nonionic surfactants [1] and derivatives of anionics [2]. The combination of gas chromatography with mass spectrometry (GC-MS) is well established, and relatively cheap dedicated instruments are available for this application. 

Gas Chromatography with Mass Spectrometry (GC/MS) has been used for the determination of polychlorinated biphenyls (PCBs) as impurities in copper phthalocyanine blue and green, as well as in PR 144. PCBs are suspected carcinogens, and their concentration in commercial products is limited in the United States to a max-... 

The carbon number distribution of technical secondary alkanesulfonates determined by pyrolysis gas chromatography and mass spectrometry (GC-MS) is shown in Fig. 13 together with the corresponding carbon number pattern of the raw material paraffins obtained by GC [16]. Pyrolysis was performed in a crucible-modified SGE pyrojector after covering the mixture with quartz wool. The presence of up to 10 wt % of disulfonates in technical alkanesulfonates is demonstrated by fast atom bombardment and mass spectrometry (FAB-MS) (Fig. 14) [24],... 

A new technique has been developed to analyze a- and (3-endosulfan concentrations in human urine (Vidal et al. 1998). Samples are mixed with a buffer solution and then passed through solid phase extraction cartridges for analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). 

Confirmation of suspected residue findings relies on the various chromatographic principles of cleanup and determination (GPC, NP-LC, GC), and is further supported by re-analysis of the final extract(s) on a GC stationary phase of different polarity, providing modified selectivity, or by the use of GC with specific mass spectrometric detection [GC/MS or gas chromatography/tandem mass spectrometry (GC/MS/MS)]. 

MS detection does not necessarily require as highly resolved GC separations as in the case of selective detectors because the likelihood of an overlapping mass spectral peak among pesticides with the same retention time is less than the likelihood of an overlapping peak from the same element. Unfortunately, this advantage cannot always be optimized because SIM and current gas chromatography/tandem mass spectrometry (GC/MS/MS) methods, it is difficult to devise sequential SIM or MS/MS retention time windows to achieve fast GC separations for approximately > 50 analytes in a single method. 

Behavioral bioassays are inextricably linked with chemical studies to decipher the information content of olfactory signals (Albone 1984). As a complement to the experimental approach described above, several research groups have applied chemical approaches, particularly gas chromatography and mass spectrometry (GC-MS),... 

Structure elucidation of semiochemicals by modern NMR-techniques (including HPLC/NMR) is often hampered by the very small amounts of available material and problems in the isolation of pure compounds from the complex mixtures they are embedded in. Thus, the combination of gas chromatography and mass spectrometry, GC/MS, is frequently the method of choice. Determination of the molecular mass of the target compound (by chemical ionisation) and its atomic composition (by high resolution mass spectrometry) as well as a careful use of MS-Ubraries (mass spectra of beetle pheromones and their fragmentation pattern have been described [27]) and gas chromatographic retention indices will certainly facihtate the identification procedure. In addition, the combination of gas chromatography with Fourier-transform infrared spec-... 

Fig. 6. An example showing the use of gas chromatography and mass spectrometry (GC-MS) for identifying reaction products on zeolites. Styrene was first reacted for ca. 30 min on activated zeolite HY at 298 K in a sealed glass tube the sample was extracted using toluene as solvent, and the extracts were then analyzed with GC-MS. The total ion chromatogram of the extracts (a) shows three major peaks eluting at 13.83, 13.93, and 14.31 min, respectively. The peak at 14.31 min was readily identified as the linear dimer. The peaks at 13.83 and 13.93 min show equal ion intensity and nearly identical mass spectra (the mass spectrum of the 13.93-min peak is shown in (b)), and these were assigned to the cis and trans isomers of the cyclic dimer.

For the accurate interpretation of a positive hair analysis result, it is necessary to subject hair to specially developed wash and extraction procedures. During the development of these procedures, we discovered several important properties of hair, properties which were essential for defining three unique wash kinetic criteria and their cutoff levels which, in conjunction with washing, enhance the acciuacy of the interpretation of a positive hair analysis result. Additional certainty can be achieved by the measurement of metabolites or metabolite/drug ratios, by the development of ultrasensitive gas chromatography/tandem mass spectrometry (GC/MS/MS) or ion... 

Combined gas chromatography and mass spectrometry (GC/MS), in particular, equipped with high-resolution capillary GC, is quite powerful for identification and quantification of known alkaloids from small quantities of plant materials. 

Although cholesterol is about 10-fold less reactive in autoxidation than PUFA there is still interest in the products that have been associated with oxidant stress. Cholesterol, free and bound to ester, is measured after separation into free and ester cholesterol by selective extraction and hydrolysis using gas chromatography-tandem mass spectrometry (GC/MS/MS) [61]. Oxidized cholesterol, oxysterols, can be analyzed using LC-MS/MS with a minimum of manipulation or by using GC/MS/MS after derivatization [62-66]. 

The direct combination of packed column gas chromatography and mass spectrometry (GC/MS), usually with computer attachment, has been used routinely for over a decade to identify and quantify mixture components. Capillary GC/MS, with its high chromatographic resolution has now also become an established technique and refinements in all aspects of the combination are continually being reviewed (5, 6). 

Free fatty acids can be efficiently extracted with acidified mixture of hexane/ tert-butyl methyl ether. Acids, esters, and salts are saponified with sodium hydroxide and esterified (transesterified) with methanol. Methyl esters are conveniently separated and determined by gas chromatography with a flame-ionization detector. Combination of gas chromatography and mass spectrometry, GC-MS, is one of the methods of choice for analysis of methylated fatty acids. Equivalent chain length of fatty acid can be calculated from the retention time. 

Versatility, no solvent use, low cost, detection limits in the mid- to low-ppt range, small volumes of samples required for sampling, the possibility of automation, and ruggedness are the main advantages of SPME. The use of SPME in combination with gas chromatography-mass spectrometry (GC-MS) or gas chromatography-tandem mass spectrometry (GC-MS-MS) is a powerful mean for identification of volatile and semivolatile organic compounds, i.e., aliphatic and aromatic hydrocarbons, polychlorinated biphenyls, pesticides, phenols, fla-... 

Due to the high performance of modern triple quadrupole mass spectrometers for PCDD/PCDF and dl-PCB analysis (Kotz et al., 2012) further amendments of the criteria for confirmatory methods for inclusion of MS/MS (tandem mass spectrometry) have been set in effect with the European Commission Regulation No 709/2014 of 20 June 2014. Technical progress and developments have shown that the use of gas chromatography/tandem mass spectrometry (GC-MS/MS) should be allowed for use as a confirmatory method for checking compliance with the... 

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