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.
- Amino acid sequence,
- apoproteins,
- bacteriorhodopsins,
- electrophoresis,
- capillary,
- hydrofluoric acid,
- isotope labeling,
- microscopy,
- electron,
- molecular weight,
- myoglobin,
- peptides,
- proteins,
- serum albumin,
- silicon dioxide,
- spectrometry,
- mass,
- electrospray ionization,
- trypsin
Available at: http://works.bepress.com/timothy-veenstra/323/