MEASURING ARRANGEMENT AND METHOD FOR REGISTERING AN ANALYTE CONCENTRATION IN A MEASURED MEDIUM

• US 20130213807A1
• Filed: 08/08/2011
• Published: 08/22/2013
• Est. Priority Date: 08/10/2010
• Status: Active Grant

• Current Assignee: Endress+Hauser Conducta Gesellschaft FUER Mess- und Regeltechnik mbH+Company KG
• Original Assignee: Endress + Hauser Conducta Gesellschaft Fur Mess- Und Regeltechnik Mbh + Co. Kg
• Inventors: Hanko, Michael, Wilhelm, Thomas
• Granted Patent: US 9,568,450 B2
• Time in Patent Office: Days
• US Class Current: 204/407
• CPC Class Codes: G01N 27/30 Electrodes, e.g. test electrodes; Half-cells G01N27/414 takes precedence
• CPC Class Codes: G01N 27/302 pH sensitive, e.g. quinhydron, antimony or hydrogen electrodes ion selective electrodes G01N27/333, glass electrodes G01N27/36
• CPC Class Codes: G01N 27/333 Ion-selective electrodes or membranes glass electrodes G01N27/36
• CPC Class Codes: G01N 27/416 Systems G01N27/27 takes precedence
• CPC Class Codes: G01N 27/4167 pH electrodes therefor G01N27/302, G01N27/36
• CPC Class Codes: G01N 27/48 using polarography, i.e. measuring changes in current under a slowly-varying voltage
• CPC Class Codes: G01N 27/49 Systems involving the determination of the current at a single specific value, or small range of values, of applied voltage for producing selective measurement of one or more particular ionic species

Abstract

A measuring arrangement for registering an analyte concentration in a measured medium includes a three electrode arrangement having a working electrode, a reference electrode and a counter electrode. The working electrode includes an analyte-insensitive, redox mediator, and the reference electrode a pH-sensitive electrode. The counter electrode can be formed of an inert, electrically conductive material. The measuring arrangement can be embodied to provide a desired voltage between the working electrode and the reference electrode and to register the electrical current flowing, in such case, through the measured medium, between the counter electrode and the working electrode.

Claims

1-12. -12. (canceled)

13. A measuring arrangement for registering an analyte concentration in a measured medium, comprises:

a three electrode arrangement having a working electrode, a reference electrode and a counter electrode, wherein;

said working electrode includes an analyte-insensitive redox mediator and said reference electrode an analyte sensitive electrode.

14. The measuring arrangement as claimed in claim 13, further comprising:

a control circuit, especially a potentiostatic, control circuit, which is embodied to provide between said working electrode and said reference electrode a desired voltage, and to register, in such case, the electrical current flowing through the measured medium between said counter electrode and said working electrode.

15. The measuring arrangement as claimed in claim 13, wherein:

the measuring arrangement is embodied to perform, by means of the three electrode arrangement, amperometric measurements, especially voltammetric measurements.

16. The measuring arrangement as claimed in claim 13, further comprising:

a function generator, which is embodied to specify a voltage curve to be provided between said working electrode and said reference electrode, wherein;

the measuring arrangement is embodied to register the electrical current flowing through the measured medium between said working electrode and said counter electrode, as a result of providing the predetermined voltage curve, as a function of the voltage provided between said reference electrode and said working electrode.

17. The measuring arrangement as claimed in claim 14, further comprising:

an evaluating system, which is embodied to ascertain, from an electrical current curve between said working electrode and said counter electrode registered in the case of a voltammetric measurement, a value of the voltage lying between said working electrode and said reference electrode, at which voltage the electrical current curve has a local extremum associated with an oxidation or reduction of the redox mediator, and from this value to derive the analyte concentration in the measured medium.

18. The measuring arrangement as claimed in claim 13, wherein:

said redox mediator is selected from the group consisting of Prussian, or Berlin, blue, analogs of Prussian, or Berlin, blue, derivatives of Prussian, or Berlin, blue, ferrocene, ferrocene analogs, ferrocene derivatives, ferroin, the redox system Ce³⁺/Ce⁴⁺ and the redox system I⁻

/I₂.

22. The measuring arrangement as claimed in claim 13, wherein:

said reference electrode comprises an inner electrolyte, especially pH-buffered, inner electrolyte, accommodated in a housing and an analyte sensitive membrane terminating the housing in a region provided for contact with the measured medium.

23. The measuring arrangement as claimed in claim 13, wherein:

said reference electrode comprises an analyte sensitive, ISFET-chip, especially a pH-sensitive, ISFET-chip.

24. A method for determining an analyte concentration in a measured medium, wherein a working electrode, a reference electrode and a counter electrode are brought into electrically conductive contact with the measured medium, wherein:

the working electrode comprises an analyte-insensitive redox mediator, the counter electrode an inert material and the reference electrode an analyte sensitive electrode; and

a voltammetric measurement is performed and, based on the voltammetric measurement, the analyte concentration is ascertained.

21. The measuring arrangement as claimed in claim 24, wherein:

said working electrode comprises an inner electrolyte accommodated in a housing, into which an inner electrolyte extends a potential sensing element connected with a working electrode connection of the measuring arrangement, and

said inner electrolyte is in electrically, or electrolytically, conductive contact with the measured medium via a liquid junction, especially a diaphragm.