Multidimensional separation prior to mass spectrometry: Getting closer to the bottom of the iceberg

While prefractionation has previously been shown to improve results in MS analysis, a novel combination provides an additional dimension of separation: protein fractionation by SDS-PAGE followed by IEF of tryptic peptides before separation by RP-LC [Atanassov and Urlaub, Proteomics 2013, 13, 2947-2955]. This three-step separation procedure prior to MS/MS substantially increases proteome coverage and represents a further step toward a more comprehensive analysis of complex proteomes.