Electrophoresis gas-phase

Electrophoresis, which is discussed in Chapter 26, is the migration of ions in solution under the influence of an electric field. Ion mobility spectrometry is gas-phase electrophoresis, which separates ions according to their size-to-charge ratio. Unlike mass spectrometry, ion mobility spectrometry is capable of separating isomers. 

Ion mobility spectrometry Gas phase separation of ion/molecule clusters at atmospheric pressure generi-cally gas phase electrophoresis. 

McLean, J. A. Russell, D. H. New vistas for mass spectrometry-based proteomics and biotechnology Rapid two-dimensional separations using gas-phase electrophoresis/ion mobihty-mass spectrometry. 

Breci, L., Hattrup, E., Keeler, M., Letarte, J., Johnson, R., Haynes, PA. (2005). Comprehensive proteomics in yeast using chromatographic fractionation, gas phase fractionation, protein gel electrophoresis, and isoelectric focusing. Proteomics 5, 2018-2028. 

L. Breci, E. Hattrup, M. Keeler, J. Letarte, R. Johnson, and P. A. Haynes. Comprehensive Proteomics in Yeast Using Chromatographic Fractionation, Gas Phase Fractionation, Protein Gel Electrophoresis, and Isoelectric Focusing. Proteomics, 5(2005) 2018-2028. 

Mass spectrometry is traditionally a gas phase technique for the analysis of relatively volatile samples. Effluents from gas chromatographs are already in a suitable form and other readily vaporized samples could be fairly easily accommodated. However the coupling of mass spectrometry to liquid streams, e.g. HPLC and capillary electrophoresis, posed a new problem and several different methods are now in use. These include the spray methods mentioned below and bombarding with atoms (fast atom bombardment, FAB) or ions (secondary-ion mass spectrometry, SIMS). The part of the instrument in which ionization of the neutral molecules occurs is called the ion source. The commonest method of... 

At the opposite extreme of molecular size from DNA, small molecules and free atoms can be ionized and subjected to electrophoresis in the gas phase. The technique, named ion mobility spectroscopy (IMS) or plasma chromatography, would better be called gaseous electrophoresis for consistency. The uses and theory of this method can be found in the literature [31,32]. 

In ESI, the endergonic transfer of ions from solution into the gas phase is accomplished by desolvation. The electric field penetrates the analyte solution and separates positive and negative ions in an electrophoresis-like process. The positive charges accumulate on the surface of the droplets when the surface tension is exceeded, the characteristic Taylor cone is formed and the microspray occurs (Wihn and Mann, 1994). At this point, the droplets are close to their stability... 

The Retina Foundation was a unique place in the late 1950s. The five-story, old tenement house was rebuilt and filled with the most modern biomedical research equipment available. We had analytical ultra-centrifuge, free electrophoresis machine, nuclear magnetic resonance machine, equipment to determine C-14 in the gas phase (before scintillation counters existed), electron microscope, tissue culture equipment with microcinematography, and a superb instrument shop to make new research tools. 

After polypeptides have been separated by polyacrylamide electrophoresis, they can be electrophoretically transferred to a glass-fibre filter paper that has been treated with 3-aminopropyltriethoxysilane and covalently bonded using 4,4 -phenylene diisothiocyanate. The glass-fibre disc loaded with as little as 10 ag of polypeptide can be placed directly into a gas-phase sequenator (Aebersold et al., 1988). 

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