A Sol-Gel-Modified Poly(methyl methacrylate) Electrophoresis Microchip with a Hydrophilic Channel Wall

摘要

A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall.To fabricate such a device,tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h.After removing the excess TEOS,the channel was filled with an acidic solution for 3 h.Subsequently,the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip.The water contact angle for the sol-gel-modified PMMA was approx=27.4° compared with approx=66.3° for the pure PMMA.In addition,the electro-osmotic flow increased from 2.13X 10~(-4) cm~2 V~(-1)s~(-1) for the native-PMMA channel to 4.86X10~(-4) cm~2 V~(-1) s~(-1) for the modified one.The analytical performance of the sol-gel-modified PMMA microchip was demonstratedfor the electrophoretic separation ofseveral purines,coupled with ampero-metric detection.The separation efficiency of uric acid increased to74882.3 m~(-1) compared with14730.5 m~(-1) for native-PMMA microchips.The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.