Membrane preconcentration-capillary electrophoresis tandem mass spectrometry (mPC-CE-MS/MS) in the sequence analysis of biologically derived peptides.

We demonstrate the use of membrane preconcentration capillary electrophoresis tandem mass spectrometry (mPC-CE-MS/MS) for sequencing peptides at the sub-100 femtomole level. In particular by loading the mPC-CE cartridge off-line with a pressurized bomb apparatus, 100 mul solutions can be loaded in <5 min. Furthermore, mPC-CE-MS in conjunction with on-line transient isotachophoresis carried out in 25 mum i.d. capillaries results in enhanced resolution and theoretical plate values as compared to convention 50-75 mum i.d. capillaries. We show that this is a powerful new approach in the sequencing of biologically derived compounds from complex mixtures such as MHC class I peptides.