On-column sample enrichment for capillary electrophoresis sheathless electrospray ionization mass spectrometry: evaluation for peptide analysis and protein identification.
Although several designs have been advanced for coupling sample enrichment devices to a sheathless electrospray ionization-mass spectrometry (MS) interface on a capillary electrophoresis (CE) column, most of these approaches suffer from difficulties in fabrication, and the CE separation efficiency is degraded as a result of the presence of coupling sleeves. We have developed a design that offers significant improvements in terms of ease of fabrication, durability, and maintenance of the integrity of the CE-separated analyte zones. Capillaries with different inside and outside diameters were evaluated to optimize the performance of the CE-MS system, resulting in a mass limit of detection of 500 amol for tandem MS analysis of a standard peptide using a 20-microm-i.d. capillary. The improved design incorporates an efficient method to preconcentrate a sample directly within the CE capillary followed by its electrophoretic separation and detection using a true zero dead-volume sheathless CE-MS interface. Testing of this novel CE-MS system showed its ability to characterize proteomic samples such as protein digests, in-gel-digested proteins, and hydrophobic peptides as well as to quantitate ICAT-labeled peptides.
Laboratory of Proteomics and Analytical Technologies and Image Analysis Laboratory, SAIC-Frederick, Inc., National Cancer Institute at Frederick, P.O. Box B, Frederick, Maryland 21702, USA. Janini@mail.ncifcrf.gov
George M
GM
Janini
Ming
M
Zhou
Li-Rong
LR
Yu
Josip
J
Blonder
Michelle
M
Gignac
Thomas P
TP
Conrads
Haleem J
HJ
Issaq
Timothy D
TD
Veenstra
D000595:Amino Acid Sequence; D001059:Apoproteins / Q000737:chemistry; D001436:Bacteriorhodopsins / Q000032:analysis / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D005345:Fibrinopeptide B / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007553:Isotope Labeling; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009211:Myoglobin / Q000737:chemistry; D010446:Peptide Fragments / Q000032:analysis; D010455:Peptides / Q000032:analysis* / Q000737:chemistry; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods; D014357:Trypsin / Q000378:metabolism
D001059:Apoproteins; D009211:Myoglobin; D010446:Peptide Fragments; D010455:Peptides; D011506:Proteins; D012709:Serum Albumin; C010857:apomyoglobin; D005345:Fibrinopeptide B; D001436:Bacteriorhodopsins; D012822:Silicon Dioxide; D045304:Cytochromes c; D014357:Trypsin; D006858:Hydrofluoric Acid