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Published November 1, 2005 | public
Journal Article

Microfluidic Platform for Liquid Chromatography−Tandem Mass Spectrometry Analyses of Complex Peptide Mixtures


A microfluidic chip that integrates all the fluidic components of a gradient liquid chromatography (LC) system is described. These chips were batch-fabricated on a silicon wafer using photolithographic processes and with Parylene as the main structural material. The fabricated chip includes three electrolysis-based electrochemical pumps, one for loading the sample and the other two for delivering the solvent gradient; platinum electrodes for delivering current to the pumps and establishing the electrospray potential; a low-volume static mixer; a column packed with silica-based reversed-phase support; integrated frits for bead capture; and an electrospray nozzle. The fabricated structures were able to withstand pressures in excess of 250 psi. The device was used to perform a liquid chromatography−tandem mass spectrometry (LC−MS/MS) analysis of a mixture of peptides from the trypsin digestion of bovine serum albumen (BSA). Gradient elution through the 1.2-cm column was performed at a flow rate of 80 nL/min. Compared to the analysis of the same sample using a commercial nanoflow LC system, the chromatographic resolution was nearly as good, and the total cycle time was significantly reduced because of the minimal volume between the pumps and the column. Results demonstrate the potential of mass-produced, low-cost microfluidic systems capable of performing LC separations for proteomics applications.

Additional Information

© 2005 American Chemical Society. Received for review June 20, 2005. Accepted September 2, 2005. This work was supported by grants from the Public Health Services (NIHRR06217 and CA33752). We thank Roger E. Moore for assistance with some of the mass spectrometry experiments.

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