Simple fabrication and use of fritless chromatographic microchips packed with reversed-phase silica particles for small-molecule separations

ANYL 142

Frank A. Gomez, fgomez2@calstatela.edu, Schetema Stevens, schetema@yahoo.com, Attila Gaspar, gaspara@tigris.unideb.hu, Lilia Hernandez, aupbfe@yahoo.com, and Menake E. Piyasena, merandy9@yahoo.com. Department of Chemistry and Biochemistry, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
We describe the development of thin microfluidic chips (less than 100 microns in total thickness) for use in chromatographic separations. In this work, chips are fabricated from poly(dimethylsiloxane) (PDMS) and reversed-phase silica beads (C18) are incorporated within the microfluidic channels. The packing of C18 modified silica beads into the microfluidic channels is made possible by the use of a novel magnetic valve and the hydrophobic nature and excellent elasticity of PDMS. Separation of dyes and other small molecules have been performed utilizing the microchips and reproducible and high resolution separation results have been obtained. The thin chips allow for the use of an external fiber optics assembly for detection thereby omitting the incoporation of fiber optics during the fabrication step. The thin chips are low cost, disposable and require little material and have great potential in a variety of applications. Detailed construction and characterization of the chips are discussed.