Characterization of a solid-phase extraction device for discontinuous on-line preconcentration in capillary electrophoresis-based peptide mapping.

摘要: Peptide mapping by capillary electrophoresis (CE) with UV detection is problematic for the characterization of proteins that can only be obtained at low micromolar concentrations. Dilution peptide fragments during digestion protein further reduce sensitivity in to point where analysis sub-micromolar concentrations not possible. A remedy this problem preconcentration (sample enrichment) proteolytic digest solid-phase extraction (SPE). To minimize non-specific adsorptive losses sample handling, on-line SPE-CE preferred. However, packed-inlet always feasible due either instrument or limitations. We describe here a simple method discontinuous SPE-CE, specifically applied low-pH separation buffer after enzyme microreactor. The system does require application pressure electrophoretic overcome reversed electroosmotic flow because preconcentrator device disconnected from before electric field applied. Up 500-fold factor achieved device, which reused many samples. Parameters such as volume desorption solution, adsorption/desorption (chromatographic) process, reproducibility packing SPE and effects concentration on map are investigated.