A CE-MALDI interface based on the use of prestructured sample supports.
We have developed an off-line coupling of capillary electrophoresis (CE) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) based on CE fraction collection onto prestructured MALDI sample supports. Analyte carryover and detection sensitivity were investigated using a standard peptide mixture. Low femtomole amounts were detected, and no noticeable carryover was discovered. The performance of the method was evaluated with a mixture of tryptic digests of proteins from a human fetal brain cDNA expression library. The total number of identified peptides was increased from 47 to 211 when the CE-MALDI interface was used compared to direct MALDI-MS analysis. Sequence coverage with CE-MALDI was in the 25-60% range for the different proteins, corresponding to an increase of 1.3-4.9 times relative to that obtained with MALDI-MS of the crude mixture. Fractionation of sample components also facilitated protein identification by MALDI postsource decay analysis. Our initial results suggest this CE-MALDI interface can be used for the analysis of complex peptide mixtures isolated from biological tissues.
Johnson
T
T
Institute of Clinical Neuroscience, Göteborg University, SE-431 80 Mölndal, Sweden. toj@neuro.gu.se
Bergquist
J
J
Ekman
R
R
Nordhoff
E
E
Schürenberg
M
M
Klöppel
K D
KD
Müller
M
M
Lehrach
H
H
Gobom
J
J
D001923:Brain Chemistry; D019075:Electrophoresis, Capillary; D005333:Fetus / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D010455:Peptides / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D010455:Peptides