Apparatus and method for performing microfluidic manipulations for chemical analysis

Abstract

A microchip apparatus and method provide fluidic manipulations for a variety of applications, including sample injection for microchip liquid chromatography. The microchip is fabricated using standard photolithographic procedures and chemical wet etching, with the substrate and cover plate joined using direct bonding. Capillary electrophoresis is performed in channels formed in the substrate. Injections are made by electro-osmotically pumping sample through the injection channel that crosses the separation channel, followed by a switching of the potentials to force a plug into the separation channel.

What is claimed is:  
     
         1 . A method of controlling fluid flow in an interconnected channel structure having at least three ports, comprising: 
 actively controlling the electric potential at the at least three ports to create differences in potential sufficient to cause fluid to move through the interconnected channel structure in a controlled manner.