Contemporary mass spectrometers have exceptional sensitivity, providing detection at attomole concentrations.64 However, such sensitivity is largely confined to pure solutions and not yet achievable in complex biological samples. For example, the dynamic range of proteins present in plasma spans 10 to 11 orders of magnitude (e.g. 4 × 1010 pg/ml for albumin compared to few pg/ml for some interleukins).65 Current MS instrumentation can only resolve 4–6 orders of magnitude. While proteomics offers a comprehensive analysis of high abundant proteins it has not yet overcome the difficulties of analysing low abundant proteins in complex samples. Unlike PCR or antibody-based techniques, proteomics lacks the ability to amplify low abundant proteins to aid detection and instead relies on enriching the target proteome.