Processed samples are first separated by a proprietary system combining high-resolution electrokinetic focusing of peptides and nano-scale reversed phase liquid chromatography. The capillary-based system features automated interfacing between the two orthogonal separation dimensions. Final separation and detection is performed by mass spectrometry, enabling accurate mass determination and fragmentation of isolated peptides to determine sequence and post-translational modification sites. A typical Gemini™ analysis consumes 1-10 micrograms of total protein extracted from a sample size of fewer than10,000 targeted cells.