A multidimensional liquid chromatography-tandem mass spectrometry platform to improve protein identification in high-throughput shotgun proteomics
A new on-line multidimensional system for sequential trapping and individual elution and separationof peptides based on their molecular weight is described. By sequentially using two chemically differenttrapping columns, a polymethacrylate monolith and a packed C18 one, peptides from complex samplescan be on-line trapped and divided into two fractions, containing respectively mainly medium-large pep-tides and smaller peptides. Then, by means of two switching valves working in parallel, the two fractionswere individually separated by reversed phase chromatography.