COMPREHENSIVE ONLINE LC LC MS OF PROTEINS

This is a description of a comprehensive two-dimensional liquid chroma tography (LC) system for the separation of protein mixtures. This syst em uses cation-exchange chromatography followed by reversed-phase chro matography(RPLC). The two LC systems are coupled by an eight-port valv e equipped with two storage loops and under computer control. The RPLC effluent is sampled by both a UV detector and an electrospray mass sp ectrometer. In this way, complex mixtures of large biomolecules can be rapidly separated, desalted, and analyzed for molecular weight in les s than 2 h. The system's utility is demonstrated with a mixture of sta ndards and an Escherichia coli cell lysate.