Biomedical Engineering Reference
In-Depth Information
ionspray method, nebulization (formation of droplets) is performed in the presence of an
applied potential. Atmospheric pressure chemical ionization (APCI) is a nebulizer for
formation of droplets at high-flow rates and an additional electrode that provides an
ionizing corona discharge. Recently developed low-flow ESI has several advantages
which provide increased sampling efficiency, better desolvation, reduction of the gas
load to the vacuum system, and less analate (Hendrickson and Emmett, 1999 and
references therein).
The high field ESI FT-ICR mass spectrometry permits routine analysis for proteins
as large as 67 kDa and with the highest mass 112 kDa. The favorable ration mass/charge
for the method detection is 500 < m/z < 2500 with the mass accuracy about 100 ppb.
The ESI FT-ICR MS is used for the investigation of the hydrogen/deuterium exchange,
conformational analysis, complex mixture analysis, and for establishing elemental
composition from isotopic fine structure.
The ESI-MS is used for simultaneous detection of enzymatic products and
chemically identical standards, which are distinguished by the deuterium labeling
(Gerbert et al., 1999). The method starts with the design of a synthetic conjugate
molecule that contains a target substrate for the desired enzyme. The conjugate molecule
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