Gas chromatography-mass spectrometer GC-MS

Figure 10 Gas Chromatography/Mass Spectrometer (GC/MS) of Silicone Extractables...

Fig. 4.1 Schematic diagram showing the components of a computer-controlled gas chromatography-mass spectrometer (GC-MS) instrument.

The method developed by Mari et al. (2009) consisted of solid-phase extraction by Bond Elut Certify LRC cartridges (Varian, Harbor City, CA), and derivatiza-tion of samples with BSTFA. A gas chromatography—mass spectrometer (GC—MS, Thermoquest Trace GC/Finnigan Polaris Q MS) was employed for the analysis of cocaine, benzoylecgonine, and morphine. Recoveries were higher than 87% for all the compounds and the limits of quantification were lower than 25 ng/L. 

The combined techniques of gas chromatography/mass spectrometry (gc/ms) are highly effective in identifying the composition of various gc peaks. The individual peaks enter a mass spectrometer in which they are analyzed for parent ion and fragmentation patterns, and the individual components of certain resoles are completely resolved. 

When the gas chromatograph is attached to a mass spectrometer, a very powerful analytical tool (gas chromatography-mass spectrometry, GC-MS) is produced. Vapour gas chromatography allows the analyses of mixtures but does not allow the definitive identification of unknown substances whereas mass spectrometry is good for the identification of a single compound but is less than ideal for the identification of mixtures of... 

In gas chromatography/mass spectrometry (GC/MS), the effluent from a gas chromatograph is passed into a mass spectrometer and a mass spectrum is taken every few milliseconds. Thus gas chromatography is used to separate a mixture, and mass spectrometry used to analyze it. GC/MS is a very powerful analytical technique. One of its more visible applications involves the testing of athletes for steroids, stimulants, and other performance-enhancing drugs. These drugs are converted in the body to derivatives called metabolites, which are then excreted in the... 

Gas chromatography/mass spectrometry (GC/MS) is the synergistic combination of two powerful analytic techniques. The gas chromatograph separates the components of a mixture in time, and the mass spectrometer provides information that aids in the structural identification of each component. The gas chromatograph, the mass spectrometer, and the interface linking these two instruments are described in this chapter. 

Characterization of various types of damage to DNA by oxygen-derived species can be achieved by the technique of gas chromatography-mass spectrometry (GC-MS), which may be applied to DNA itself or to DNA-protein complexes such as chromatin (Dizdaroglu, 1991). For GC-MS, the DNA or chromatin is hydrolysed (usually by heating with formic acid) and the products are converted to volatile derivatives, which are separated by gas chromatography and conclusively identified by the structural evidence provided by a mass spectrometer. Stable isotope-labelled bases may be used as internal standards... 

Once into the 21st century, hyphenated instrumentation (i.e., those that couple two instruments together) became prevalent in laboratories. This is the combination of two or more, often different, instruments. In simple terms, the purpose is to first separate the analyte of interest and then to identify it. This takes place using a sample injected into the combined instruments. The most common of the hyphenated instruments is the gas chromatograph, the output of which is fed into a mass spectrometer to produce a gas chromatography-mass spectrometry (GC-MS) [35],... 

We discussed the fundamentals of mass spectrometry in Chapter 10 and infrared spectrometry in Chapter 8. The quadrupole mass spectrometer and the Fourier transform infrared spectrometer have been adapted to and used with GC equipment as detectors with great success. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-infrared spectrometry (GC-IR) are very powerful tools for qualitative analysis in GC because not only do they give retention time information, but, due to their inherent speed, they are also able to measure and record the mass spectrum or infrared (IR) spectrum of the individual sample components as they elute from the GC column. It is like taking a photograph of each component as it elutes. See Figure 12.14. Coupled with the computer banks of mass and IR spectra, a component s identity is an easy chore for such a detector. It seems the only real... 

Preliminary structural characterization was carried out on the soluble products of treatment with BF3/CH3OH (or LiAlH (8), in order to verify the similarity of our samples to materials studied previously (8-11). Gas chromatography-mass spectrometry (GC-MS) (Finnigan 3300 spectrometer) was used to establish the molecular ion and fragmentation patterns solution-state 13C NMR (IBM Instruments WP-200 spectrometer) was employed for quantitation of CH2, CH2OH, and CHOH moieties. 

Gas Chromatography-Mass Spectrometry (GC-MS) analysis was carried out on a Varian instrument coupled to a Nermag R10-10 quadrupole mass spectrometer. Separation was achieved on a JW DB1 (60 m, 0 0.32, film thickness 0.25 p) capillary column. 

Gas chromatographv-mass spectrometry. Gas chromatography-mass spectrometry (GC-MS) was carried out using a Hewlett-Packard 5840 gas chromatograph connected to a VG-70S mass spectrometer operated at 70 eV with a mass range m/z 40-800 and a cycle time of 1.8 s. The gas... 

The GC is often connected to a mass spectrometer. Mass spectrometry (MS) breaks samples apart and separates the ionized fragments by mass and charge. Vast libraries of comparison fragments make computer-aided identification of materials possible even when the sample is very small. Most forensic laboratories have access to a combined gas chromatograph/mass spectrometer (GC/MS). High pressure liquid chromatography (HPLC) separates many types of drugs and may also be combined with MS. 

Combined gas chromatography-mass spectrometry (GC-MS) takes advantage of the separating power of the gas chromatograph and the identification power of mass spectrometry. The gas chromatograph separates the components and provides retention time data and the mass spectrometer identifies the components. The combined instrumentation has the potential to provide very useful information in FDR casework. Figure 16.5 illustrates a quadrupole mass spectrometer. 

The gas chromatograph is particularly useful when it is linked to a mass spectrometer. This combination is called gas chromatography-mass spectrometry (GC-MS). 

Gas-Chromatography Mass Spectral (GC-MS) Analyses. Several different studies were carried out. The main study was done using a Finnigan MAT 4500 series quadrupole mass spectrometer and a 60 m X 0.32 mm l.d. DB-1 bonded fused silica capillary GLC column. The column was programmed from 25-250°C at 4° per minute with an inlet pressure of 14 psi. Chemical ionization (Cl) mass spectra on some of the components were also obtained using a VG Micromass 70/70 mass spectrometer with Isobutane as the reactant gas. 

Another possible detector for GC is the mass spectrometer. This detector (which was in fact developed independently as a stand-alone instrument) offers the capability of compound identification. Extensive literature is available regarding gas chromatography/mass spectrometry (GC/MS) analysis of organic molecules [e g. 37,... 

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