MICROVIALS ON A SILICON-WAFER FOR SAMPLE INTRODUCTION IN CAPILLARY ELECTROPHORESIS

A multi-sample holder produced by photolithographic and anisotropic etching techniques on a monocrystalline silicon wafer is described. Well defined volumes are created by utilizing the crystal orientations of the silicon material. By using step and repeated lithography, a large number of identical cavities can be obtained on a single chip. The surface is covered with a thin film of gold, which serves as a cathode during electrokinetic injections. Evaluation was carried out by injecting a mixture of pd(A) oligonucleotides (40-60) bases from a 118-nl sample well on to a 50 mum I.D. polyacrylamide-filled gel column. When compared with injections from classical vials, no additional zone broadening was observed.