AN INTEGRATED MICROFLUIDICS TANDEM MASS-SPECTROMETRY SYSTEM FOR AUTOMATED PROTEIN-ANALYSIS

We describe an integrated analytical system consisting of a microfluid ics device micromachined using photolithography/etching technology, a panel of computer-controlled high-voltage relays, and an electrospray ionization tandem mass spectrometer. Movement of solvents and samples on the device and off the device to the mass spectrometer was achieved by directed electroosmotic pumping induced by the activation of a sui table constellation of high-voltage relays. The system was used for th e sequential automated analysis of protein digests. We demonstrate low femtomole per microliter sensitivity of detection and compatibility o f the system with the automated analysis of proteins separated by two- dimensional gel electrophoresis.