Electrochemical detector
First Claim
1. An electrochemical detector for detecting electroactive substances, comprising:
- an electrochemical cell for receiving liquid including the substances to be detected,a working electrode, an auxiliary electrode, a reference electrode, each of said three electrodes being in conductive connection with the liquid in the electrochemical cell,a potentiostat for maintaining during electrochemical detection a constant potential difference between the liquid in the electrochemical cell and the working electrode, with the potentiostat being coupled during electrochemical detection to the reference electrode and to the auxiliary electrode, andsignal processing circuitry for deriving an electric signal indicative of the current created at the working electrode by electroactive substances,in combination with monitoring means for determining and monitoring the potential of the reference electrode, said monitoring means comprising;
disconnecting means for disconnecting the working electrode from the signal processing circuitrygrounding means for applying a predetermined potential to the end of the reference electrode opposite to the end in contact with the electrochemical cell,an electrometer circuit being operative to perform a substantially currentless measurement of the potential of the reference electrode, andswitching means for disconnecting the auxiliary electrode from the potentiostat and for connecting the auxiliary electrode to an electrometer circuit.
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Accused Products
Abstract
An electrochemical detector comprising an electrochemical cell (11), a working electrode (1), an auxiliary electrode (2), a reference electrode (3), a potentiostat (4), and a circuit (7,8) for deriving a signal indicative of the current developed at the working electrode additionally comprises means for monitoring and determining the potential of the reference electrode (3). These means comprise an electrometer circuit (9) which can be connected via a switch (S2) to the auxiliary electrode (2) to measure the potential of the reference electrode. During the measurement, the working electrode (1) is disconnected from the circuit (7,8) which is at the same time connected to the electrometer circuit (9) via switch (S1). The invention permits to recognize measuring errors associated with instabilities in the reference electrode potential (FIG. 1).
21 Citations
9 Claims
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1. An electrochemical detector for detecting electroactive substances, comprising:
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an electrochemical cell for receiving liquid including the substances to be detected, a working electrode, an auxiliary electrode, a reference electrode, each of said three electrodes being in conductive connection with the liquid in the electrochemical cell, a potentiostat for maintaining during electrochemical detection a constant potential difference between the liquid in the electrochemical cell and the working electrode, with the potentiostat being coupled during electrochemical detection to the reference electrode and to the auxiliary electrode, and signal processing circuitry for deriving an electric signal indicative of the current created at the working electrode by electroactive substances, in combination with monitoring means for determining and monitoring the potential of the reference electrode, said monitoring means comprising; disconnecting means for disconnecting the working electrode from the signal processing circuitry grounding means for applying a predetermined potential to the end of the reference electrode opposite to the end in contact with the electrochemical cell, an electrometer circuit being operative to perform a substantially currentless measurement of the potential of the reference electrode, and switching means for disconnecting the auxiliary electrode from the potentiostat and for connecting the auxiliary electrode to an electrometer circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification