An LC/MS/MS Interface for off-line deposition of capillary LC separations onto MALDI target plates

Library Number:
WA22002
Part Number:
WA22002
Author(s):
Finch, Jeffrey W.;Wall, Daniel B.;Chen, Wieben;Berger, Scott J.;Cohen, Steven A.
Source:
Desorption 2002 Conference
Content Type:
Posters
Content Subtype:
Other Symposium
Compounds:
Protein; Peptides; Apomyoglobin; Yeast Ribosomal
Column:
Symmetry® C18 3.5 µm Steel 3 mm 150 mm
Peptide mass fingerprinting (PMF) by MALDI-TOF/MS is used extensively for protein identification in the field of Proteomics. The most common PMF application is for identification of proteins from in-gel digests of 1-D gel bands or 2-D gel spots. Digest samples are typically cleaned up using a ZipTipjTM and spotted onto a target well of the MALDI plate. However, ion suppression effects can create difficulties with this approach, particularly when analyzing complex digest samples where low abundance proteins are in the presence of one or more high abundance proteins. These effects will often result in the inability to detect peptides from the low abundance proteins. One alternative approach is the coupling of capillary scale chromatography with MALDI, in order to separate the peptides prior to analysis, thus reducing complexity of the digest mixture. This presentation highlights the advantages of using an LC-MALDI interface, the LC-MALDIprepTM sample deposition module, for deposition of capillary-scale HPLC separations on to a moving MALDI target plate in continuous sample tracks or spots. The system utilizes a conductive substrate which is pre-coated with matrix and attached to a standard MALDI target plate. This approach has some unique advantages including: a) a reduction in ion suppression effects due to spatial separation of the analyte on the MALDI target, b) spatial focusing of the sample into an area that is three times smaller than the area of traditional sample wells, c) higher solution volumes can be desolvated and depositied to the target, d) a stable format that allows storage of protein digest separations to target plates which can be analyzed months later. Improved PMF results using the LC-MALDIprepTM versus the traditional ZipTipTM and spot approach for MALDI-TOF/MS will be presented, along with a discussion of about potential benefits of LC deposition for MALDI MS/MS analysis.

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