Patent ID: 8262989

Claim:
A biosensor system comprising: a pair of essentially flat heat sinks ( 9 , 10 ), arranged with their surfaces facing each other; a pair of Peltier elements ( 11 ) thermally attached to said heat sinks ( 9 , 10 ), one element ( 11 ) on each heat sink ( 9 , 10 ), on said facing surfaces; and a thermostated compartment ( 3 , 4 , 5 ), the heat sinks ( 9 , 10 ) being suspended inside said compartment ( 3 , 4 , 5 ) by heat insulating members ( 8 a , 8 b ; 160 ) connected to a respective block ( 3 , 4 ; 80 , 100 ) such that heat exchange between the heat sink and the thermostated compartment ( 3 , 4 , 5 ) is kept minimal, wherein there is a gap between the Peltier elements ( 11 ) in which gap an insertable, generally flat biosensor unit ( 12 ) is positioned and fits snugly, said biosensor unit ( 12 ) comprising a reaction chamber in which a reaction is to be run, the heat of reaction of which can be measured by said Peltier elements, wherein the biosensor unit comprises thin foils ( 20 ; 340 ) defining opposite walls of said reaction chamber ( 14 ; 300 ) defined by the biosensor unit ( 12 ; 260 ), a thickness of the reaction chamber being small in relation to dimensions of walls defined by the foils, the thickness being in an interval of 0.3-0.5 mm, and wherein the Peltier elements ( 11 ; 200 ) are arranged so as to be in a heat conducting contact with said thin foils when the biosensor unit ( 12 ; 260 ) is in an operative position between the Peltier elements ( 11 ; 200 ), and the heat conducting contact area between Peltier elements ( 11 ; 200 ) and the foils ( 20 ; 340 ) corresponds to the total reaction chamber wall area defined by said foils ( 20 ; 340 ), wherein a heat capacity of the heat sinks is selected such that a thermal impact from a heat flow in the heat sinks creates a thermal disturbance of an order of <1-100 ppm.