Differential Proteomic Analysis of Complex Mixtures by Label-Free nLC MS/MS.

After over two decades of constant evolution, proteomics can be truly considered nowadays as a high-throughput technique. Latest advances performed in sample preparation, instrumentation, and data analysis tools enable proteome-wide detection and quantification of proteins in complex samples.Label-free quantification by nanoscale liquid chromatography coupled online to tandem mass spectrometry (nLC MS /MS ) is a straightforward procedure for relative protein quantification. This approach allows to get deeper insights of what molecular changes are involved in the biological system we want to study in an unbiased manner.This chapter describes methods for sample preparation prior to mass spectrometry analysis. Besides, we describe a standard acquisition method, and some common bioinformatics analyses that help extracting biologically relevant information out of the achieved data.