Chemical analysis methods mass spectrometry

DENDRAL uses a set of rule-based methods to deduce the molecular structure of organic chemical compounds from chemical analysis and mass-spectrometry data. This process includes detecting structural fragments, generating structural formula from these fragments, and verifying it by determining the correlation between... 

Desorption chemical ionisation (DCI) mass spectrometry has been used for detecting additives extracted from polymers [51,52] by a solvent as volatile as possible. To use the DCI probe, 1 -2 iL of the sample, in solution, are applied to the probe tip, composed of a small platinum coil, and after the solvent has been allowed to evaporate at room temperature, the probe is inserted into the source. The sample is then subject to fast temperature ramping. DCI does not seem to be the most suitable mass-spectrometric method for analysis of dissolved polymer/additive matrices, because ... 

Fredline VF, Taylor PJ, Dodds HM, Johnson AG (1997) A reference method for the analysis of aldosterone in blood by high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry. Anal Biochem 252 308-313... 

In the early history of gas chromatogra-phy/olfactometry (GC/O vn/tgu), the goal of GC/O analysis was to determine when an odor elutes from a GC in order to identify it. The analysis yielded a list of times and, with appropriate standards, retention indices. When combined with other chemical analysis methods, such as mass spectrometry (MS), a name for a particular odorant could be proposed. Comparing both the chemical and sensory properties of the odorant with those of authentic standards allowed researchers to identify the odorant with considerable certainty. The number of odorants that are detected, however, is determined by a number of factors, including the design of the olfactometer, the fraction of the extract injected, and, as we now suspect, the genetics of the sniffer. 

Flamini, R., Dalla Vedova, A., De Rosso, M. and Panighel, A. (2007) A New Sensitive and Selective Method for Analysis of Ochratoxin A in Grape and Wine by direct liquid chromatography/surface activated chemical ionization-tandem mass spectrometry, Rapid Commun. Mass Spectrom. 21(22), 3737-3742. 

The methods used can be conveniently arranged into a number of categories (a) fractionation by precipitation (b) fractionation by distillation (c) separation by chromatographic techniques (d) chemical analysis by spectrophotometric techniques (infrared, ultraviolet, nuclear magnetic resource. X-ray fluorescence, emission, neutron activation), titrimetric and gravimetric techniques, and elemental analysis and (e) molecular weight analysis by mass spectrometry, vapor pressure osmometry, and size exclusion chromatography. 

Figure 8.3. The SACI/MS2 and MS3 fragmentation patterns of OTA and ZAN [M+H]+ ions. (Reprinted from Rapid Communications in Mass Spectrometry 21, Flamini et al., A new sensitive and selective method for analysis of och-ratoxin A in grape and wine by direct liquid chromatography/surface activated chemical ionization-tandem mass spectrometry, p. 3738, Copyright 2007, with permission from John Wiley Sons, Ltd.)...

Kallio, H. and Currie, G. (1993) Analysis of lowerucic acid turnip rapeseed oil by negative ion chemical ionization tandem mass spectrometry. A method giving information on the fatty acid composition in positions sn-2 and sn-lB of triglycerols. Lipids, 28, 207-215. 

The first method can be applied with about 70 elements and has a detecting sensitivity in the ppm range. The activation analysis is very sensitive but also very selective. For all chemical elements, however, mass spectrometry can be applied. With samples of a few micrograms, the detecting sensitivity lies in the ppb range [103-105]. Very high detecting sensitivities can be achieved by the use of modem surface analysis techniques, some of which were discussed in Chapter 3 Section... 

Several chemical analysis methods have been developed for the determination of palytoxin and/ or palytoxin analogues, based on chemical properties characteristic and intrinsic to the toxin. Such methods include (1) infrared spectrometry, (2) ultraviolet spectrometry, (3) mass spectrometry, (4) high-performance capillary electrophoresis, (5) thin-layer chromatography, and (6) liquid chromatography. A comparative table of the most important quantitative chemical analysis methods summarizes the main features of each method and could assist in selection of the most fit-for-purpose analysis method depending on available equipment and sensitivity required (Table 29.4). 

Fayad PB, Prevost M, Sauve S, Laser diode thermal desorption/atmospheric pressure chemical ionization tandem mass spectrometry analysis of selected steroid hormones in wastewater Method optimization and application. Anal. Chem. 2010 82(2) 639-645. 

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