Abstract: A microfabricated device for fragmenting nucleic acids present in a fluid sample, the device comprising an inlet port (20), a fragmentation cell (1), and an outlet port (10) downstream from said inlet port (20), said cell (1) being in fluid communication with said ports, and wherein said outlet port is dimensioned to impede the flow of a fluid sample out of said cell (1) so as to effect shearing of nucleic acids molecules therein.

Abstract: A microfluidic system for the concentration of particulate matter comprises a first reservoir (1) containing a buffer solution, a second reservoir (2) containing a analyte, and a third reservoir (3) containing beads suspended in a liquid. Microchannels link the reservoirs and an expanded portion (4). Hydrostatic pressure is applied to the reservoir (3) containing the beads while an electro-osmotic force (EOF) is applied between the reservoir (1) and the reservoir (3) to establish counter flows of liquids. A vortex forms in the flared portion (5) due to the counter flow of the liquids and the beads are concentrated in the vortex. By switching the EOF between reservoirs (1) and (2) the buffer solution can be replaced by the analyte to enable an analysis to be performed.

Abstract: A miniaturized detector cell (4) having a measuring chamber volume of 25 fl-1 .mu.l is described. In spite of its miniaturized construction, the detector cell has an optical path length of about 0.1-100 mm. The incident measuring light (R) is repeatedly reflected at the inner walls (23, 25, 26) of the interaction region (21 ) before it leaves the detector cell (4) again. In a preferred manner, the detector cell (4) is manufactured from silicon or quartz by photolithographic means.