Parallel mass spectrometry

Multidimensional or hyphenated instmments employ two or more analytical instmmental techniques, either sequentially, or in parallel. Hence, one can have multidimensional separations, eg, hplc/gc, identifications, ms/ms, or separations/identifications, such as gc/ms (see CHROMATOGRAPHY Mass spectrometry). The purpose of interfacing two or more analytical instmments is to increase the analytical information while reducing data acquisition time. For example, in tandem-mass spectrometry (ms/ms) (17,18), the first mass spectrometer appHes soft ionization to separate the mixture of choice into molecular ions the second mass spectrometer obtains the mass spectmm of each ion. 

Irganox 1076 [octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,6-di-t-butyl-4-methylphenol and diisooctyl phthalate were analyzed by GPC interfaced with both electrospray mass spectrometry (ESI-MS) and NMR.1 A deuterochloroform solvent was used. It was noted that a parallel arrangement was necessary to avoid backpressure on the NMR flow-probe that can... 

Deng, Y., Wu, J., Lloyd, T.L., Chi, C.L., Olah, T.V., Unger, S.E. (2002). High-speed gradient parallel liquid chromatography/tandem mass spectrometry with fully automated sample preparation for hioanalysis 30 seconds per sample from plasma. Rapid Commun. Mass Spectrom. 16, 1116-1123. 

King, R.C. et al. 2002. Description and validation of a staggered parallel high performance liquid chromatography system for good laboratory practice level quantitative analysis by liquid chromatography/tandem mass spectrometry. Rapid Commun. Mass Spectrom. 16 43. 

Fang, L. et al. 2003. Parallel high-throughput accurate mass measurement using a nine-channel multiplexed electrospray liquid chromatography ultraviolet time-of-flight mass spectrometry system. Rapid Commun. Mass Spectrom. 17 1425. 

Xu, R. et al. 2002. Application of parallel liquid chromatography/mass spectrometry for high throughput microsomal stability screening of compound libraries. J. Am. Soc. Mass Spectrom. 13 155. 

Grant R.P., Cameron C., and Mackenzie-McMurter S., 2002. Generic serial and parallel online direct injection using turbulent flow liquid chromatography/tandem mass spectrometry. Rapid Commun Mass Spectrom 16 1785. 

Hsieh S. et al., 2004. Increased throughput of parallel online extraction liquid chromatography /electrospray ionization tandem mass spectrometry system for GLP quantitative bioanalysis in drug development. Rapid Commun Mass Spectrom 18 285. 

The exact mass of an ion (4 to 6 decimal points) reliably defines its elemental and isotopic composition, while the method is called high resolution mass spectrometry. The measurements are conducted manually or automatically (computerized). Manual measurements are based on the parallel acquisition of the peak of interest with the closest peak of an ion with the known composition. Any compound with an intense ion peak with m/z value in the region +10% may serve as a marker. The most widespread markers are perfluorokerosene, perfluorotributylamine, and other polyfluorinated compounds. The use of these compounds is based on their volatility, as well as on the fact that fluorine is a monoisotopic element. In the spectra of these compounds intense ion peaks randomly cover all the range between m/z 19 and M+. ... 

The oxygen transfer from an ortho nitro group to a carbon-carbon triple bond has been studied by high-resolution mass spectrometry, linked scan techniques and chemical substitution81. Oxygen transfers to both acetylenic carbons were detected as parallel fragmentation pathways81. 

Bayliss M. Little D. Mallett D. Plumb R. Parallel ultra-high flow rate liquid chromatography with mass spectrometric detection using a multiplex electrospray source for direct, sensitive determination of pharmaceuticals in plasma at extremely high-throughput. Rapid Communications in Mass Spectrometry, 2000, 14, 2039-2045. 

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