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A CE-MALDI interface based on the use of prestructured sample supports.
T Johnson1, J Bergquist, R Ekman
1Institute of Clinical Neuroscience, Göteborg University, SE-431 80 Mölndal, Sweden. toj@neuro.gu.se
Analytical Chemistry
|May 8, 2001
Summary
We developed a capillary electrophoresis (CE) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) interface. This method enhances peptide identification and sequence coverage for complex biological samples.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Proteomics
Background:
- Direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of complex peptide mixtures can be limited.
- Capillary electrophoresis (CE) offers effective separation but requires interfacing with MS for identification.
Purpose of the Study:
- To develop and evaluate an off-line coupling method between CE and MALDI-TOF-MS.
- To improve peptide identification and sequence coverage from complex biological samples.
Main Methods:
- Developed an off-line CE-MALDI interface using CE fraction collection onto prestructured MALDI sample supports.
- Investigated analyte carryover and detection sensitivity with a standard peptide mixture.
- Evaluated method performance using tryptic digests from a human fetal brain cDNA expression library.
Main Results:
- Achieved low femtomole detection sensitivity with no noticeable analyte carryover.
- Increased identified peptides from 47 to 211 compared to direct MALDI-MS analysis.
- Enhanced protein sequence coverage by 1.3-4.9 times (25-60% range).
Conclusions:
- The developed CE-MALDI interface significantly improves peptide identification and sequence coverage for complex mixtures.
- This method facilitates protein identification, including MALDI post-source decay analysis.
- The CE-MALDI interface is suitable for analyzing complex peptide mixtures from biological tissues.