SENSOR DEVICE FOR THE PARALLEL DETERMINATION OF A CONCENTRATION OF SMALL MOLECULE SUBSTANCES AND OF A PH VALUE

Abstract

Disclosed is a sensor device (100) for the parallel determination of a concentration of small molecule substances (e.g. ethanol, glucose, etc.) and of a pH value in a solution during the course of a biotechnological process using what is known as cyclic voltammetry. Said sensor device is constructed in the form of a rod electrode. The sensor device consists at least of two rod-shaped working electrodes (102, 103), for which different conductive materials are selected in such a way that distinguishable voltage/current profiles can be determined for the small molecule substances to be determined, and of a rod-shaped reference electrode (104). The working electrodes and the reference electrode are each embedded or melted in a tubular, insulating material. Furthermore, the sensor device comprises a counter electrode (105) in the form of a hollow cylinder, within which the working electrodes and the reference electrode are mounted. In addition, the sensor device has a sensor head part (101), which comprises at least one electronic component (107) for providing desired voltage profiles for cyclic voltammetry and for signal amplification, an analysis unit (108) for control and evaluation, and an interface (109) for data transmission.

Claims

1.-12. (canceled)

13. A sensor device for the parallel determination of a concentration of small molecule substances and of a pH value during the course of a biotechnological process, the sensor device being constructed in the form of a rod electrode, the sensor device comprising: two rod-shaped working electrodes, for which different, conductive materials are selected in such a way that distinguishable voltage and/or current profiles can be determined for the small molecule substances to be determined; a rod-shaped reference electrode, wherein the working electrodes and the reference electrodes are embedded in an insulating material; a counter electrode formed as a hollow cylinder, within which the working electrodes and the reference electrode are attached; and a sensor head part which has at least one electronic component for providing desired voltage profiles for cyclic voltammetry and for signal amplification, an analysis unit for control and evaluation, and an interface for data transmission.

14. The sensor device of claim 13, wherein a first working electrode is made of palladium, a second working electrode is made of platinum, a platinum alloy or another noble metal, and the reference electrode is made of silver or silver chloride.

15. The sensor device of claim 13, wherein the working electrodes and the reference electrode are microelectrodes.

16. The sensor device of claim 13, wherein the counter electrode is configured as a hollow cylinder made from a non-corrosive, conductive material, in particular stainless steel.

17. The sensor device of claim 13, wherein glass is used as the insulating material for embedding the working electrodes and the reference electrodes.

18. The sensor device of claim 13, wherein a battery module for a power supply is also provided in the sensor head part.

19. The sensor device of claim 13, wherein a multivariant analysis method is used for the evaluation of measured signal profiles by the analysis unit.

20. The sensor device of claim 13, wherein the interface for data transmission is a wired or wireless interface.

21. The sensor device of claim 13, wherein the sensor device has a detachably attached connecting element in an area of the counter electrode being a hollow cylinder.

22. The sensor device of claim 13, wherein the sensor device is a hand-held device for laboratory operation.

23. The sensor device of claim 13, wherein the sensor head part comprises a display unit for outputting and displaying results of the analysis unit.

24. The sensor device of claim 13, wherein the sensor device is installed in a system for biotechnological processes.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0028] The invention is explained below using examples with reference to the attached FIGURE. FIG. 1 shows by way of example and schematically a sensor device for the direct and parallel determination of small molecular substances by means of cyclic voltammetry and of a pH value, which can be used during a biotechnological process.

IMPLEMENTATION OF THE INVENTION

[0029] FIG. 1 shows by way of example and schematically the sensor device 100 according to the invention for the parallel determination of small molecule substances, in particular ethanol and glucose, as well as of a pH value in a solution using cyclic voltammetry. The sensor device 100 according to the invention is constructed in the form of a rod electrode and can be produced in at least two design variants. On the one hand, the sensor device 100 can be designed as a hand-held device for laboratory operation, i.e. as an autonomously operating sensor device 100. On the other hand, the sensor device 100 can be installed, for example, in a plant for biotechnological processes (e.g. production plant). That is to say, the sensor device 100 is integrated into the system in a fixed manner, for example by screwing or another method of fastening.

[0030] The sensor device 100 according to the invention has a sensor head part 101 in which the electronics required for measurement and data transmission are accommodated, as well as an electrode part. The electrode part comprises at least two rod-shaped working electrodes 102, 103, a rod-shaped reference electrode 104, and a counter electrode 105. The working electrodes 102, 103 and the reference electrode 104 are designed as microelectrodes, for example, which ideally have a diameter in a range from 50 to 100 m. Furthermore, the working electrodes 102, 103 and the reference electrode 104 are each embedded in an insulating material. Glass or a glass tube, in which the respective electrode 102, 103, 104 is embedded or melted, can be used as the insulating material.

[0031] The working electrodes 102, 103 also consist of different, conductive materials, which are selected in such a way that, with these conductive materials, distinguishable current/voltage profiles can be determined for the small molecule substances to be determined. To determine a glucose concentration in the solution, a first working electrode 102 is made of palladium, for example. A second working electrode 103 is, for example, used to determine a pH of the solution and to determine an ethanol concentration in the platinum solution. Alternatively, platinum alloys or other noble metals can also be used for the second working electrode 103. The reference electrode 104 can be designed, for example, as a silver/silver chloride electrode.

[0032] The counter electrode 105 is designed as a hollow cylinder, in which the working electrodes 102, 103 embedded in insulating material or glass and the reference electrode 104 embedded in insulating material or glass are attached for bundling and protection. The working electrodes 102, 103 and reference electrode 104 can, for example, be glued to the counter electrode 105 designed as a hollow cylinder. The counter electrode 105 is made of a non-corroding, conductive material such as stainless steel, for example, so that cyclic voltammetric measurements are possible, but the counter electrode 105 is not attacked by the solution to be examined.

[0033] A detachable connecting element 106 or flange 106 can also be attached in the area of the counter electrode 105, which is designed as a hollow cylinder. This connecting element 106 is also designed in the shape of a hollow cylinder and can be used to connect to vessels in which the sensor device 100 is to be used.

[0034] The electronics required for the entire measurement or for cyclic voltammetry and for data transmission are located in the sensor head part 101, which can also be cylindrical. For this purpose, the sensor head part 101 comprises an electronic component 107, from which the voltages or voltage profiles necessary for cyclic voltammetry are provided and by which the signals or current/voltage profiles of the electrode part are amplified. Furthermore, the sensor head part 101 has an analysis unit 108, which can be designed as a microcontroller. The tasks of the analysis unit 108 are to control the cyclovoltammetric measurement, to digitize measured signal or current/voltage profiles and to carry out an analysis/evaluation of the measured values. This analysis or evaluation can take place, for example, by means of a so-called multivariant analysis method such as, for example, partial least square regression (PLS).

[0035] Furthermore, the analysis unit 108 can also control a data transmission via an interface 109 for data transmission, for example from the sensor head part 101 to a higher-level unit (for example a control or control unit of a plant, etc.). The interface 109 for data transmission can be designed, for example, as a wired interface, which supports standard protocols in the process industry (for example, Modbus protocol, Ethernet-based fieldbus). Alternatively, the interface 109 can also be designed, for example, as a wireless interface via which the evaluated measurement data is transmitted, for example by means of near-field communication or NFC.

[0036] The sensor head part 101 also includes a battery module 110. The electronic component 107 accommodated in the sensor head part 101 and the analysis unit 108 are supplied with energy by the battery module 110. Depending on the area of application (for example process control, ongoing analysis, quality control), the sensor device 100 can be designed as a hand-held device for laboratory operation or it can be installed in a plant for carrying out biotechnological processes.

[0037] In the embodiment of the sensor device 100 as a hand-held device for laboratory operation, the sensor head part 101 can also have a display unit as an alternative or in addition to the interface 109 for data transmission. The measured values determined with the sensor device 100, such as, for example, pH value, concentration of ethanol and glucose, etc., can be displayed and output directly on the sensor device 100 on the display unit.

[0038] For the determination of, for example, ethanol and glucose concentration as well as the pH value in a solution, the sensor device 100 with the electrode part is brought into contact with the solution to be analyzed, so that the working electrodes 102, 103, which consist of different materials (e.g. palladium and platinum), the reference electrode 104 and the counter electrode 105 are in contact with the solution. From the electronic component 107, to which the working electrodes 102, 103, the reference electrode 104 and the counter electrode 105 are connected, alternately selected potential profiles (e.g. triangular, etc.) are applied to the working electrodes 102, 103. In parallel with this, associated current profiles between the respective working electrodes 102, 103 and the counter electrode 105 as well as associated voltage profiles between the working electrodes 102, 103 and the reference electrode 104 are measured by the electronic component 107 for the applied potential profiles.

[0039] When measuring the corresponding, associated current profiles between the working electrodes 102, 103 and the counter electrode 105 and the corresponding, associated voltage profiles between the working electrodes 102, 103 and the reference electrode 104, the current profiles in particular are characteristic of a substance concentration to be determined in the solution to be analyzed. The voltage profiles measured between the working electrodes 102, 103 and the reference electrode 104 are largely predetermined by the selected potential profiles applied with the electronic component 107.

[0040] The electronic component 107 functions here, for example, as a so-called potentiostat, which in the simplest case can be used in electrochemistry as a precise DC voltage source or as a source for time-varying voltage profiles (e.g. triangle, etc.) or as a voltmeter or ammeter. The application of the potential profiles and the measurement of the respective associated current and voltage profiles between the electrodes 102, 103, 104, 105 are controlled and monitored by the analysis unit 108.

[0041] The measured current and voltage profiles or signal profiles are optionally amplified by the electronic component 107 and forwarded to the analysis unit 108. The measured signal profiles are digitized by the analysis unit 108 and evaluated, for example, using so-called multivariate analysis methods such as partial least square regression.

[0042] By evaluating the current and voltage profiles measured on working electrodes 102, 103, which are made of different materialse.g. palladium and platinumusing multivariate analysis methods, a concentration of the small molecular substances to be analyzed (e.g. ethanol, glucose, etc.) can then be determined in parallel in the solution to be analyzed. For this purpose, for example, relationships between current and voltage profiles are estimated and, for example, the concentration of the respective small molecule substance such as ethanol or glucose is determined on the basis of current peaks that occur. As a side result of the determination of the content of small molecule substances such as glucose and ethanol by means of cyclic voltammetry in the solution to be analyzed, the pH value of this solution can also be determined.

LIST OF REFERENCE SYMBOLS

[0043] 100 Sensor device [0044] 101 Sensor head part [0045] 102 First working electrode [0046] 103 Second working electrode [0047] 104 Reference electrode [0048] 105 Counter electrode [0049] 106 Detachable connecting element (flange) [0050] 107 Electronic component for providing the voltage profiles for cyclic voltammetry and for signal amplification [0051] 108 Analysis unit for control and evaluation [0052] 109 Interface for data transmission [0053] 110 Battery module for a power supply