Patent ID: 7169289

Claim:
A device for the electrochemical detection of at least one type of a biochemical molecule contained in a liquid from a group of predetermined biochemical molecules of different types, comprising: a means ( 1 ) for taking up the liquid, said means having at least one reference electrode (RE) and at least one counterelectrode (GE) and more than two working electrodes (AE 1 , AE 2 , AE 3 ), with at least one working electrode (AE 1 , AE 2 , AE 3 ) being provided for the detection of each type of a biochemical molecule, said working electrode being coated with a molecule that is complementary to the biochemical molecule to be detected, so that biochemical molecules of different types can be detected simultaneously, a current/voltage converter (S 1 , S 2 , S 3 ) being connected downstream of each of the working electrodes (AE 1 , AE 2 , AE 3 ) and having a first operational amplifier (OP 1 ) and a first resistor (R 1 ), the current/voltage converters (S 1 , S 2 , S 3 ) holding all of the working electrodes (AE 1 , AE 2 , AE 3 ) at the same potential, a means (AD) for measuring the currents flowing through the working electrodes (AE 1 , AE 2 , AE 3 ), and a potentiostat (P) for generating a predetermined voltage profile which is variable during the measurement between the working electrodes (AE 1 , AE 2 , AE 3 ) and the reference electrode (RE), said potentiostat (P) comprising a second operational amplifier (OP 2 ) and a second resistor (R 2 ), and a third operational amplifier (OP 3 ) and a third resistor (R 3 ), with the third operational amplifier (OP 3 ), to whose output the counterelectrode (GE) is connected and whose inverting input ( 0 P 3 −) is connected via the second resistor (R 2 ) to the output of the second operational amplifier (OP 2 ), being connected via the third resistor (R 3 ) to a device for generating a selectable desired voltage, with the noninverting input ( 0 P 3 +) of the third operational amplifier (OP 3 ) being grounded.