Bio-Rad Matrix-Prepared Surfaces - Manual (Page 2)

1 © 2007 Bio-Rad Laboratories, Inc.
Use
n
Peptide analysis
Introduction
Fundamental to most applications of laser desorption/ionization
mass spectrometry (LDI-MS) is the addition of matrix to the
analyte. Matrix signals interfere in the low molecular weight (MW)
range of the spectra, rendering matrix-assisted laser desorption/
ionization (MALDI)-MS and surface-enhanced laser desorption/
ionization (SELDI)-MS techniques problematic for peptide
analysis. Surface-enhanced neat desorption (SEND) technology
is unique in that the matrix is integral to the ProteinChip array
surface. The chemical noise in the spectra from the matrix is
significantly reduced when compared to addition of matrix
on-spot (particularly in the region 600 to 1,500 Da). This allows
the use of SELDI for lower MW species analysis with a reduced
amount of interfering peaks in the spectra.
The ProteinChip SEND ID array has C-18 as a functional group,
allowing the use of the array for on-chip cleanup, removing salt
and denaturant (such as urea) prior to analysis by SELDI.
The primary application of the ProteinChip SEND ID array is
peptide analysis. Successful mass determination of molecules
lower than 600 Da will be determined by how well these
molecules are ionized, desorbed, and detected by the mass
spectrometer. If laser intensity has to be increased above a
certain level to detect the molecule, the background peaks below
the 600 Da range may interfere with detection of analyte peaks.