Integration Of A Micro Liquid Chromatograph Onto A Silicon Chip

A novel concept for small volume liquid chromatography is presented. Using micromachining techniques, a planar silicon structure containing the channel system has been fabricated. A split injector, a packed small-bore column, a frit and an optical detector cell were integrated onto a silicon chip, covered by a glass chip and another silicon optical fibre positioning unit. The overall size of the assembled inicrostructure is 4.5 x 25 x 0.75 mm. The separation column volume is 0.5 /spl mu/L, and the critical extra-column dead volumes on the chip are below 2.5 nL. The smallest defined connection elements have volumes of 59 femtoliters. Theoretical considerations predict reasonable separation efficiencies and low mobile phase consumption in fast analysis times. A separation of fluorescein and acridine orange yielded a maximum of 200 theoretical plates in 3 minutes.