Patent ID: 8268245

Claim:
A microfluidic device for determining an analyte in a liquid sample that has a volume in a range from about 100 nl to about 10 μl, comprising: a transport plane comprising a flat substrate, the substrate comprising a sample application site, an examination site, and a path connecting the sample application site to the examination site, along which the liquid sample is movable from the sample application site to the examination site by acoustic surface waves or electrowetting; transducer elements attached to the substrate or located outside of the substrate, wherein the transducer elements provide movement to the liquid sample; and a cover with side walls that enable the construction of a closed microfluidic device having a pierceable septum for injecting the liquid sample, and an electrode for sensing the analyte in the liquid sample, wherein in the closed microfluidic device, the septum is aligned with the sample application site and the electrode protrudes from the cover toward the substrate at the examination site, and wherein the cover has such a shape that the distance between the cover and the sample application site is greater than the distance between the cover and the examination site, so that the liquid sample does not contact the cover at the sample application site and the electrode contacts the liquid sample at the examination site.