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WO1998003860A1 - Detecteur selectif d'ions - Google Patents

Detecteur selectif d'ions Download PDF

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Publication number
WO1998003860A1
WO1998003860A1 PCT/DE1997/001583 DE9701583W WO9803860A1 WO 1998003860 A1 WO1998003860 A1 WO 1998003860A1 DE 9701583 W DE9701583 W DE 9701583W WO 9803860 A1 WO9803860 A1 WO 9803860A1
Authority
WO
WIPO (PCT)
Prior art keywords
ion
membrane
selective
sensor according
selective sensor
Prior art date
Application number
PCT/DE1997/001583
Other languages
German (de)
English (en)
Inventor
Dagmar Henn
Christa Dumschat
Michael Borchardt
Christoph Diekmann
Original Assignee
Institut für Chemo- und Biosensorik Münster E.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Institut für Chemo- und Biosensorik Münster E.V. filed Critical Institut für Chemo- und Biosensorik Münster E.V.
Publication of WO1998003860A1 publication Critical patent/WO1998003860A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/30—Electrodes, e.g. test electrodes; Half-cells
    • G01N27/333—Ion-selective electrodes or membranes

Definitions

  • the invention relates to an ion-selective sensor according to the preamble of claim 1.
  • sensors are used in the field of chemistry and analysis to selectively display a specific ion in the presence of other ions and to measure their concentration or activity, for example.
  • ion-selective electrodes have an ion-selective membrane.
  • a potential difference arises on this membrane due to ion exchange, which is dependent on the activity of the analysis.
  • This potential difference is used in potentiometric sensors to determine the concentration. If a transfer potential is applied to the membrane, ions (ideally only the analyte ions) migrate through the membrane. A current flows that is proportional under certain conditions for the concentration of the analyte. This current is used in voltammetric concentration determination techniques.
  • Conventional sensors work with a liquid drain, ie the sensor is between the ion-selective membrane and the
  • Electrode filled with an electrolyte solution via which the contact between the ion-selective membrane and the dissipative electrodes is made.
  • the disadvantage of these sensors is that they are relatively large and complex, that the production requires many individual steps. They are therefore not suitable for single-use sensors.
  • the membrane can be applied directly to a planar surface using an automatic dosing system, which improves the reproducibility of the production.
  • an automatic dosing system which improves the reproducibility of the production.
  • the back contact between the membrane and the electrode has a constant potential and must be sufficiently current-carrying.
  • Potentiometric solid-state sensors have been produced, for example, by applying poly (vinyl ferrocene) as a redox polymer directly to a metallic wire (Hauser et al. (1995) Analytica Chimica Acta, volume 302, pages 241 to 248).
  • poly (vinyl ferrocene) as a redox polymer
  • Voltammetric measuring cells based on the ion transfer at the interface between two mutually immiscible electrolyte solutions have previously worked with two liquid phases (aqueous / organic) or, if a polymer gel-stabilized organic phase is used, also with a liquid drain.
  • a condition for ideal properties of voltammetric ion-sensitive sensors is that the resistance of the interface between the analyte solution to be analyzed and the membrane is as high as possible in comparison to the other resistances, in particular the rear surface resistance and the membrane resistance. If these conditions are met, the amperometric measurement is dominated by the interfacial resistance between the analyte solution and the membrane and not by the resistances on the back of the current to be measured. In the potentiometric measurement, the fault voltages at the rear resistors become negligibly small due to the inevitable fault currents through the electrode.
  • the object of the present invention is to provide an ion-selective sensor in which the above criteria are met and measurements with lower errors are made possible.
  • the invention is based on the idea of making the contact area between the ion-selective membrane and the conductive surface of the electrode larger than the contact area between the ion-selective membrane and the analyte solution. This is achieved by intermeshing the surfaces of the electrode and the ion-selective membrane at the contact area or by increasing this contact area by means of a cover compared to the interface between the membrane and the electrolyte solution.
  • the contact area is covered everywhere by a membrane layer of sufficient thickness, ie that the electrode does not penetrate the entire membrane, but rather a closed, pure membrane layer between the membrane and the measurement solution side Measuring solution and electrode surface so that there is no short circuit between the electrode and the solution. This also leads to a longer service life of the sensor according to the invention.
  • the contact area between the back of the membrane and the electrode is larger than the membrane / analyte solution interface. Consequently, the back resistance of the sensor is small compared to the resistance of the interface between the membrane and the electrolyte, so that the measurement signal is determined almost exclusively by the processes at the interface between the analyte solution and the membrane phase. At the same time, a high stability of the interface is achieved. The lifetime of the sensor according to the invention is also extended by the sufficient membrane covering of the electrode.
  • the sensor according to the invention is suitable, inter alia, for voltammetry and for potentiometry. In addition to, for example, cyclic voltammetry, the sensor according to the invention can also be used for combined electrochemical examination methods.
  • the contact surface of the membrane with the electrolyte solution is smooth, the interface between the membrane and the analyte solution is reduced to the smallest possible size, which is predetermined by the dimensions of the membrane. In comparison to the enlarged contact area between the membrane and the electrode, the ratio between the corresponding resistances of these contact areas also improves.
  • a membrane layer between the interlocking surface structures and the interface between the membrane and the measurement or analyte solution the thickness of which is greater than 1 ⁇ m, reliably prevents short circuits between the electrode and the electrolyte solution. Layer thicknesses of greater than 5 ⁇ m have proven to be particularly advantageous.
  • a small membrane layer thickness between the electrolyte and the electrode lowers the membrane resistance and thus further improves the electrical properties of the sensor according to the invention.
  • variable positionability of the electrode and / or as an inert matrix with a conductive coating Carrier layer within the ion-selective membrane enables the contact surface between the electrode or carrier layer and the ion-selective membrane to be placed in very close proximity to the interface between the electrolyte solution and membrane and thus a reduction in the effective membrane resistance, ie an improvement in the electrical properties of the sensor.
  • a high specific surface area of the membrane can be achieved in a simple manner by the membrane, the electrode or at least one further carrier layer, which can be regarded as part of the electrode, having a macroscopic interlocking surface, in particular a porous structure, the membrane communicates with the electrode or with the carrier layer via the electron or ion-conducting pore surface.
  • Metallic materials for example porous silver or platinum-plated platinum, are suitable for producing the surface of the electrode which engages in the back of the membrane. If a porous carrier layer is used, it can also be provided with a non-porous ion- or electron-conducting coating.
  • the membrane is applied particularly easily by pouring dissolved membrane material or polymerizing membrane materials. Because of the good ability of liquids to penetrate porous structures, this method of production is particularly suitable when using porous electrodes with or without carrier layers. In this case, the contact surface of the membrane is given a corresponding porous structure.
  • the sensor according to the invention is particularly suitable for the series production of sensors with largely constant characteristics.
  • the ion-selective membrane can have a support matrix made of glass, solids or polymers, which absorbs organic solvents, conductive salts, redox pairs, carriers or ion exchangers.
  • the construction of the sensor according to the invention becomes particularly simple if the support matrix also takes on the function of an organic solvent for a guiding principle. In this case the use of an additional solvent within the membrane is not necessary.
  • a plurality of electrodes can be arranged on the carrier material within the same ion-selective membrane or else separately from one another. This can be used, for example, in a test strip Sensor can also be housed a reference electrode.
  • FIG. 1A shows a first exemplary embodiment of the ion-selective sensor according to the invention in a top view
  • FIG. 2A shows a second exemplary embodiment of the ion-selective sensor according to the invention in a top view
  • FIG. 3 shows the head of the ion-selective sensor according to Fig. 2A, 2B in cross section.
  • FIGS. 1A and 1B represent an ion-selective sensor according to the invention in plan view and cross section.
  • a conductor track 2 made of platinum is applied to a strip 11 made of ceramic as substrate or carrier.
  • This conductor track 2 is partially covered by a polymer layer 3 and has on one of its sides an exposed contact area 13 for the electrical connection of the sensor to other devices.
  • the polymer layer 3 and the strip 11 made of ceramic form the encapsulation of the sensor.
  • another material for example a polymer or a silicon, can also be selected.
  • the platinum is platinum-coated.
  • a membrane 1 made of PVC is cast into this porous platinum, the membrane 1 finally enclosing the porous platinum to the outside.
  • the contact area or the contact area between the porous platinum as an ion- or electron-conducting material and the membrane is enlarged. Overall, this results in a sensor that has a small back resistance.
  • FIGS. 2A and 2B show a further ion-selective sensor according to the invention in top view and in cross section.
  • Figure 3 shows the head of the sensor of Figures 2A and 2B.
  • the sensor consists of an elongated strip of hot-melt adhesive film 3, on which a conductor track 2 made of silver is arranged in the longitudinal direction. This conductor track 2 is at one end of the strip 1 expanded to a silver ring 9.
  • the strip 3 and the spacer 7 have a circular, concentrically arranged opening.
  • a circular disk 4 made of blue tape filter paper is arranged concentrically on the spacer 7 as a carrier layer, the diameter of which is larger than the diameter of the silver ring 9.
  • the filter paper 4 is vapor-coated on the side facing the spacer 7 and the silver ring 9 with a silver layer which penetrates into the pores of the filter paper 4.
  • the silver layer 8 is coated with silver tetra- (4-chlorophenyl) borate.
  • An ion-selective membrane 1 with a PVC support matrix is embedded in the opening of the spacer 7, which extends into the pores of the filter paper 4 and also into areas of the filter paper that are covered by the spacer 7. This means that an electrode contact with a high specific surface is at least partially arranged in the membrane 1.
  • the membrane 1 completely covers the filter paper 4 within the opening.
  • the ion-selective membrane contains tetradodecyl ammonium tetrakis (4-chlorophenyl) borate as the conductive salt.
  • the side of the filter paper 4 facing away from the membrane 1 is covered by a second hot-adhesive film 11 as a carrier, which projects beyond the silver ring 9 and is welded to the hot-adhesive film 3 and forms an encapsulation with the latter.
  • Figs. 2A, 2B and 3 shows a fully encapsulated ion selective sensor in the form of the flat measuring strip. Due to the porous structure of the filter paper 4, due to the high specific surface area of the filter paper 4, a very large interface between the membrane and the contacting silver is achieved with nevertheless very small external dimensions of the electrode. The large ratio between the contact area between membrane and electrode and the interface between analyte solution and membrane ensures that the signals from this sensor are essentially determined by the processes at the interface between analyte solution and membrane phase. Appropriate dimensioning of the spacer allows the volume and the thickness of the membrane to be determined as desired and the distance between the membrane / analyte interface and the back contact to be selected as desired, in particular very small. This leads to a further improvement in the long-term stability and the signal quality of the sensor according to the invention.
  • Electron transfer between membrane 1 and silver electrode 8, 9 is made possible by the silver / silver tetrakis (4-chlorophenyl) borate system.
  • the silver layer 8 is coated with silver tetrakis (4-chlorophenyl) borate either by electrolytic coating of the silver surface from a solution before the membrane is applied to the electrode or by electrolysis from the membrane due to its tetradodecyl content - Ammonium tetrakis (4-chlorophenyl) borate contains the corresponding anion.
  • the ion-selective membrane is introduced into the filter paper 4 and into the opening 10 by a solution in organic solvents from PVC and others substances that influence selectivity, such as ionophores or the like, are poured into opening 10.
  • the spacer 7 does not prevent this solution from penetrating between the spacer 7 and the filter paper 4 and thus also into the filter paper in areas that are covered by the spacer 7.
  • the head of the sensor according to FIG. 3 again shows a layering of second hot-melt film 11, filter paper 4, vapor-deposited silver layer 8 on the surface and in the pores of the filter paper 4, silver ring 9, spacer 7 and first hot-melt film 3.
  • the foil layer 3 is somewhat thinner in the region of the spacer, so that there is an intermediate space 14 between the spacer 7 and the filter paper 4.
  • Hot-melt film 3 a PVC membrane was poured in by pouring dissolved PVC and evaporating the solvent. The PVC solution also spread below the spacer 7 in the intermediate space 12 and into the porous structure of the filter paper 4, so that there is a large contact area of the membrane 1 with the evaporated silver layer 8.
  • the surface of the ion-selective membrane facing the analyte solution is halved in comparison to the rear surface Diameter, which optimizes the desired ratio of the interface resistances.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

L'invention concerne un détecteur sélectif d'ions. Les détecteurs de ce type s'utilisent dans le domaine de la chimie et des techniques d'analyse, pour mettre en évidence de manière sélective un ion déterminé en présence d'autres ions et de mesurer par exemple sa concentration. Ce détecteur sélectif d'ions se caractérise en ce qu'il comporte une surface de contact sensiblement plus importante entre la membrane et l'électrode, par rapport au contact entre la membrane sélective d'ions et la solution d'analyte. A cet effet, la membrane sélective d'ions et l'électrode s'interpénètrent dans la zone de cette surface de contact, par exemple par une structure poreuse, et/ou la surface de contact de la membrane en direction de la solution d'analyte est diminuée par une couche électriquement ou chimiquement inerte. Il est essentiel en outre que la membrane située entre les structures superficielles qui s'interpénètrent et l'interface en direction de la solution d'analyte présente une épaisseur déterminée, de manière à exclure tout risque de court-circuit entre l'électrode et la solution d'analyte. Les signaux du détecteur sélectif d'ions sont ensuite déterminés par potentiométrie ou voltamétrie, essentiellement uniquement par les processus à l'interface entre la membrane (1) et la solution d'analyte.
PCT/DE1997/001583 1996-07-23 1997-07-23 Detecteur selectif d'ions WO1998003860A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19631530.1 1996-07-23
DE1996131530 DE19631530C2 (de) 1996-07-23 1996-07-23 Ionenselektiver Sensor

Publications (1)

Publication Number Publication Date
WO1998003860A1 true WO1998003860A1 (fr) 1998-01-29

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Application Number Title Priority Date Filing Date
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DE (1) DE19631530C2 (fr)
WO (1) WO1998003860A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007130417A2 (fr) 2006-05-01 2007-11-15 Nanopack, Inc. Revêtements barrières pour films et structures
WO2010117900A1 (fr) 2009-04-08 2010-10-14 Nanopack, Inc. Films et structures barrières aux arômes
WO2013019833A1 (fr) 2011-08-01 2013-02-07 Nanopack, Inc. Revêtements barrières pour films et structures
JP2015510120A (ja) * 2012-02-08 2015-04-02 シーメンス アクチエンゲゼルシヤフトＳｉｅｍｅｎｓ Ａｋｔｉｅｎｇｅｓｅｌｌｓｃｈａｆｔ ラテラルフローアッセイによる液状試料の電気化学的分析のための装置及び方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10353938A1 (de) * 2003-11-18 2005-06-23 Fresenius Medical Care Deutschland Gmbh Sensorkarte zur Bestimmung von Analyten in Flüssigkeits- oder Gasproben und Verfahren zur Herstellung einer solchen Sensorkarte
DE112016001536A5 (de) * 2015-04-02 2017-12-28 Martin Aicher Vorrichtung und Verfahren zur qualitativen und/oder quantitativen Bestimmung eines ionischen Analyten in einem Fluid

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4133735A (en) * 1977-09-27 1979-01-09 The Board Of Regents Of The University Of Washington Ion-sensitive electrode and processes for making the same
FR2624611A1 (fr) * 1987-12-09 1989-06-16 Electronique Appliquee Ste Lyo Capteur potentiometrique homogene
DE4333348A1 (de) * 1992-10-02 1994-04-07 Hitachi Ltd Ionenselektive Elektrode und Durchflußzelle mit einer solchen Elektrode
US5344547A (en) * 1993-02-18 1994-09-06 Vlasov Yuri G Polycrystalline ion selective electrode
DE4427921A1 (de) * 1994-08-06 1996-02-15 Forschungszentrum Juelich Gmbh Chemische Sensoren, insbesondere Biosensoren, auf Siliciumbasis

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DE4137261C2 (de) * 1991-11-13 1995-06-29 Meinhard Prof Dr Knoll Miniaturisiertes Sensorelement zur Bestimmung von Stoffkonzentrationen in Flüssigkeiten und Verfahren zu seiner Herstellung
AUPM506894A0 (en) * 1994-04-14 1994-05-05 Memtec Limited Novel electrochemical cells
AT402452B (de) * 1994-09-14 1997-05-26 Avl Verbrennungskraft Messtech Planarer sensor zum erfassen eines chemischen parameters einer probe
DE4442253A1 (de) * 1994-11-28 1996-05-30 Bayer Corp N D Ges D Staates I Elektrochemischer Enzymbiosensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4133735A (en) * 1977-09-27 1979-01-09 The Board Of Regents Of The University Of Washington Ion-sensitive electrode and processes for making the same
FR2624611A1 (fr) * 1987-12-09 1989-06-16 Electronique Appliquee Ste Lyo Capteur potentiometrique homogene
DE4333348A1 (de) * 1992-10-02 1994-04-07 Hitachi Ltd Ionenselektive Elektrode und Durchflußzelle mit einer solchen Elektrode
US5344547A (en) * 1993-02-18 1994-09-06 Vlasov Yuri G Polycrystalline ion selective electrode
DE4427921A1 (de) * 1994-08-06 1996-02-15 Forschungszentrum Juelich Gmbh Chemische Sensoren, insbesondere Biosensoren, auf Siliciumbasis

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
K. CAMMANN: "NEW SENSING PRINCIPLES FOR ION DETECTION", SENSORS AND ACTUATORS B: CHEMICAL, vol. B35, no. 1-3, September 1996 (1996-09-01), LAUSANNE, CH, pages 26 - 31, XP000641378 *
M. BORCHARDT: "DISPOSABLE ION-SELECTIVE ELECTRODES", SENSORS AND ACTUATORS B: CHEMICAL, vol. B25, no. 1/3, April 1995 (1995-04-01), LAUSANNE, CH, pages 721 - 723, XP000532853 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007130417A2 (fr) 2006-05-01 2007-11-15 Nanopack, Inc. Revêtements barrières pour films et structures
US8080297B2 (en) 2006-05-01 2011-12-20 Nanopack, Inc. Barrier coatings for films and structures
WO2010117900A1 (fr) 2009-04-08 2010-10-14 Nanopack, Inc. Films et structures barrières aux arômes
WO2013019833A1 (fr) 2011-08-01 2013-02-07 Nanopack, Inc. Revêtements barrières pour films et structures
US10851259B2 (en) 2011-08-01 2020-12-01 Nanopack, Inc. Barrier coatings for film and structures
JP2015510120A (ja) * 2012-02-08 2015-04-02 シーメンス アクチエンゲゼルシヤフトＳｉｅｍｅｎｓ Ａｋｔｉｅｎｇｅｓｅｌｌｓｃｈａｆｔ ラテラルフローアッセイによる液状試料の電気化学的分析のための装置及び方法
US10359388B2 (en) 2012-02-08 2019-07-23 Siemens Aktiengesellschaft Arrangement and method for the electrochemical analysis of liquid samples by means of lateral flow assays
US10514353B2 (en) 2012-02-08 2019-12-24 Siemens Aktiengesellschaft Arrangement and method for the electrochemical analysis of liquid samples by means of lateral flow assays

Also Published As

Publication number Publication date
DE19631530A1 (de) 1998-01-29
DE19631530C2 (de) 2000-03-09

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