“…Pre-separation steps Pre-separation steps Solid-liquid separation Protein depletion or protein fractionation by any of the separation techniques (a) Filtration [180] (b) Centrifugation [181] Precipitation (a) Salt [182] (b) Organic solvent [183] (c) Polymer [184] (d) Detergent [185] Chromatographic steps Identification steps Ion exchange chromatography Two-dimensional gel electrophoresis Hydrophobic interaction chromatography [186] Mass spectrometry (coupled to liquid chromatography) Affinity chromatography [187] Orthogonal chromatography Gel filtration chromatography [188] Two-dimensional chromatography Radial flow chromatography [189] Direct analysis of large protein complexes (DALPC) Perfusion chromatography [190] Isoelectric focusing using nonporous reverse phase HPLC (IEF-NP RP HPLC) Expanded bed chromatography [42,43] Displacement chromatography [33,34] Bioimaging Monoliths [191] Microarray profiling Non-chromatographic steps Microfluidics Aqueous two phase extraction [67][68][69] Three phase partitioning [63,64] Reverse micellar extraction [192] Crossflow ultrafiltration [193] Preparative electrophoresis [194] The techniques listed here are illustrative and not all-inclusive. In the 'proteomics' scenario, separation is often synonymous with identification.…”