WO2006085761A1 - Électrode de référence, module à membrane pour utilisation dans celle-ci et procédé de fabrication de celle-ci - Google Patents

Électrode de référence, module à membrane pour utilisation dans celle-ci et procédé de fabrication de celle-ci Download PDF

Info

Publication number
WO2006085761A1
WO2006085761A1 PCT/NL2006/000071 NL2006000071W WO2006085761A1 WO 2006085761 A1 WO2006085761 A1 WO 2006085761A1 NL 2006000071 W NL2006000071 W NL 2006000071W WO 2006085761 A1 WO2006085761 A1 WO 2006085761A1
Authority
WO
WIPO (PCT)
Prior art keywords
membrane module
reference electrode
ceramic
particles
fluid
Prior art date
Application number
PCT/NL2006/000071
Other languages
English (en)
Inventor
Frans Mulckhuijse
Original Assignee
Hydrion B.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 Hydrion B.V. filed Critical Hydrion B.V.
Publication of WO2006085761A1 publication Critical patent/WO2006085761A1/fr

Links

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
    • G01N27/301—Reference electrodes

Definitions

  • the invention relates to a reference electrode, comprising a ceramic membrane module fabricated of partly interconnected ceramic particles forming a porous membrane, wherein a first surface of the ceramic membrane module is in contact with a fluid in the reference electrode and a second surface can be contacted with a fluid to be analysed.
  • the present invention further relates to a ceramic membrane module for use in a reference electrode .
  • the invention finally relates to a method of fabricating a ceramic membrane module according to the invention .
  • Measuring electrodes are generally known in the art . From NL 1014256 , for example, an electrode according to the preamble is known. According to that publication, the membrane must at all times comprise a non-polar iono- phoric material , for which reason the outside of the membrane is sealed in order to form an impenetrable barrier for the ionophoric material . The obligatory presence of the ionophoric material and the seal provided for it on the membrane form a disadvantage for the electrode' s fabrication and use .
  • a further electrode that works according to the " solid state" principle .
  • a chamber of the electrode contains a solid salt .
  • the solid salt is separated from the fluid to be analysed by means of a membrane .
  • the salt dissolves gradually and exits via the membrane .
  • the solubility rate is very variable and cannot be regulated.
  • This electrode does not provide a reproducible method of measuring.
  • gel electrodes are also known, as described in US 5 071 537 and FR 02 10734. However, the principle applied here differs altogether from the principle applied in the present invention.
  • the use of a ceramic membrane module in a reference electrode is already known in the art .
  • a non-porous body of a ceramic material is subj ected to lithographical or micromechanical treatments in order to provide channels through the ceramic membrane .
  • Such a method is described in the international patent application under publication number WO 00/75648.
  • the problem with the prior art membrane module is that the processes are difficult and costly. In order to create through-channels of a consistent shape and dimension, such that the porosity formed in this manner is consistent throughout the entire membrane module, the treatments must be executed with great precision.
  • this known membrane module is susceptible to clog- ging. Once a channel is obstructed it is not easily cleared. This seriously impairs the porosity. As a result, the reference electrode behaves unreliably, so that the known reference electrode needs to be calibrated regularly. It is the obj ect of the invention to provide an improved ceramic membrane module.
  • An additional obj ect of the invention is to provide an improved reference electrode.
  • the obj ect of the invention is to provide an improved method for the fabrication of a membrane module .
  • the invention provides a reference electrode according to the preamble, characterised in that the fluid in the reference electrode is a calibration fluid that can be fed through the membrane into the fluid to be analysed.
  • the flow rate at which the calibration fluid can be fed through the membrane into the fluid to be analysed is preferably
  • This may be accomplished, for example, by exerting a pres- sure on the calibration fluid with the aid of, for example, compressed gas or a pump, more specifically a micro- pump .
  • the second surface is at least partly covered by an upper layer that is im- permeable for both fluids, in order to reduce the exchanging surface area. If the surface is partly covered, the surface area permeable for the calibration fluid can be adjusted via the membrane to a desired value, so as to allow an accurate regulation of the flow rate.
  • the invention further provides a ceramic membrane module for use in a reference electrode, characterised in that the particles have a substantially identical diameter of X nm, wherein X ranges from 40-450 nm, and wherein preferably 60% of the particles , preferably at least 75% , more preferably at least 90%, and still more preferably at least 99%, have a diameter in the range from 0.9 -X - 1.1 -X, more preferably from 0.95 -X - 1.05 -X, still more preferably from 0.99 -X - 1.01 -X.
  • the advantage of the ceramic membrane module ac- cording to the invention is that it is very easy to fabricate, while nonetheless the porosity can be determined accurately. Because the individual ceramic particles are partly interconnected, a three-dimensional porous structure is obtained. The chance of clogging is therefore very slight .
  • the result of consistent porosity and insignificant susceptibility to clogging is a membrane module in a reference electrode that generates a more consistent po- tential , provides a more stable signal , and consequently provides a more precise measurement .
  • the particles have a substantially identical diameter of X nm, wherein X lies in the range from 40 - 450 nm and wherein preferably 99% of the particles have a diameter in the range from 0.9 -X - 1.1 -X, more preferably from 0.95 -X - 1.05 -X, still more preferably from 0.99 -X - 1.01 -X . If the ceramic particles have such a narrow particle size range, the porosity will be defined very precisely.
  • the particles are stacked as close packing, preferably ac- cording to a cubic close packing or a hexagonal close packing, said particles being connected with each other on the contact surfaces .
  • close packing preferably ac- cording to a cubic close packing or a hexagonal close packing, said particles being connected with each other on the contact surfaces .
  • the porosity is approximately 26% .
  • the voids content ranges from 26 to
  • a ceramic material is inert with regard to most fluids .
  • the usual materials known in the art may be used.
  • Preferred is a starting compound or a combination of starting compounds capable of producing a ceramic material , preferably at least one of an oxide, a carbide, a nitride and a boride, such as one or several of zirconium oxide, aluminium oxide, silicon nitride, silicon carbide, titanium oxide and titanium carbide . All these substances are very wear-resistant and very resistant to low pH values . In addition, all these substances are biologically inert . However, other known starting compounds for the manufacture of ceramic materials can be used just as well .
  • the size of the pores is to a large extent determined by the diameter of the ceramic particles .
  • the diameter of the particles ranges preferably from 40-450 nm, more preferably from 100-400 run. If the diameter X of the ceramic particles is approximately 200 run, the pore size is shown to range from 50-70 run. Such an embodiment is preferred.
  • Other preferable embodiments of the ceramic membrane module according to the invention will become apparent from the following description, as well as from the remaining subclaims .
  • the invention relates to a method for fabricating a ceramic membrane module according to the invention, comprising the regular stacking of ceramic particles and the subsequent sintering of the particles so as to obtain a coherent porous mass of ceramic particles that are superficially connected with each other .
  • a ce- ramie membrane module is very robust and has a precisely defined pore size .
  • the signal that can be obtained with this reference electrode is very accurate.
  • the chance of the membrane module becoming obstructed is also very slight thanks to the fact that the porosity is oriented three-dimensionalIy, such that alternative feed-through passages for the reference fluid through the membrane module will be guaranteed.
  • the ceramic membrane module according to the invention is especially very suitable for incorporation into the reference electrode according to the invention .
  • the membrane module is particularly preferred for the membrane module to be fabricated such that it comprises two surfaces , which are disposed substantially parallel to and at a distance from each other .
  • the flow of calibration fluid through the module can then be calculated quite simply.
  • the invention relates to a method for the fabrication of a ceramic membrane module, comprising the step of covering the second surface with a material that is substantially impermeable to the calibration fluid and the fluid to be analysed, so as to form an upper layer thereon, and of subsequently removing a portion of the applied upper layer so as to form a further to be determined, freely accessible flow-through surface on the mem- brane, wherein the removal is realised by, for example, drilling, milling or the like .
  • the method used for removing a portion of the upper layer preferably affords the possibility of previously determining which surface area is to be made accessible.
  • Fig. 1 shows a schematic cross section of a reference electrode according to the invention.
  • FIGS. 2 , 3 and 4 show a detailed view of the membrane module of the reference electrode .
  • Fig. 5 is a representation of measuring results from a first test using a reference electrode according to the invention.
  • Fig . 6 shows a representation of measuring re- suits from a second test using a reference electrode according to the invention.
  • the entire external surface of the membrane may be covered with a paste (optionally to cure) followed by drilling or milling a small hole into it .
  • a paste optionally to cure
  • drilling or milling a small hole into it a surface of a known diameter is obtained.
  • the membrane has possibly been drilled, it is possible that the surface of the membrane at that hole is no longer exactly parallel to the other surface of the membrane . Nonetheless , a membrane fabricated in this manner is also considered to have two substantially parallel surfaces .
  • Fig. 1 shows a reference electrode 1 , which is comprised substantially of a housing 2 and a chamber 3 substantially enclosed by the housing 2.
  • the chamber 3 contains a reference fluid 4.
  • the chamber 3 also contains an electrode 5 , which is connected via a first end of the sensor 1 with an electrical connection 7 for conducting an electric signal .
  • the second end of the sensor 1 is provided with and substantially closed off by a membrane module 6.
  • Fig. 1 also shows a pump 8 for pumping a reference fluid from a storage vessel 9 into the chamber 3 of the reference electrode .
  • a reference electrode 1 as shown in Fig. 1 will be described in more detail .
  • a reference electrode 1 as shown in Fig. 1 is immersed in a fluid to be analysed such that the part of the sensor 1 with the membrane module 6 is in the fluid.
  • the pump 8 pumps a small amount of reference fluid from the storage vessel 9 into the chamber 3 , which chamber 3 was already completely filled with reference fluid 4 , such that a continuous stream of reference fluid 4 is pumped from the chamber 3 through the membrane module 6 into the fluid to be analysed.
  • Said amount of reference fluid being pumped through the membrane module 6 is very small , such that the amount of contamination from the fluid to be analysed is undetectable .
  • the reference electrode 1 shown in Fig. 1 works exactly in the manner known in the art .
  • the membrane module 6 should be in communication with the housing in such a way that all the outflowing fluid passes through the porous membrane module 6 and not along the membrane module 6.
  • the pump system 8 provides for a constant and ad- justable pressure with which the reference fluid is fed through the ceramic membrane . This makes it possible to produce a very consistent and regulated continuous outflow and thus to generate a very stable electrical signal .
  • the constant pressure may also be produced by means of a propellant, optionally contained in a balloon-like chamber, in the sensor .
  • There are different ways of connecting the ceramic membrane module according to the present invention with the reference electrode .
  • the Figures 2 , 3 and 4 show different detailed views of possible forms of connecting the ceramic membrane module with the housing 2 of the reference electrode 1. Fig.
  • the ceramic mem- brane module may, for example, be connected with the housing 2 by means of adhesion using, for example, glue or the like .
  • Fig . 3 shows an alternative embodiment, wherein the ceramic membrane module 6 is connected with an inner wall surface of the housing 2 along a circumferential surface 10.
  • the connection may be provided, for example, by means of adhesion.
  • a third alternative embodiment is shown in Fig . 4 , wherein the ceramic membrane module 6 is initially in- serted into a recess in the end of the housing 2 , substantially in a manner identical to that shown in Fig.2 , but wherein the membrane module 6 is positioned by a screw- detachable coupling member 12 , connected by means of thread 11 with the housing 2.
  • An alternative manner of fabricating the ceramic membrane module entails the moulding or extrusion of ceramic particles . In that case the particles will probably not be placed in accordance with by approximation ideal close packing, for example, a cubic close packing or a hexagonal close packing. However, in cases where such a precise definition of the pore size is not necessary, a method of this kind provides an inexpensive alternative .
  • the ceramic particles are preferably packed by means of sedimentation and are subsequently sintered.
  • the membrane module 6 is provided with an upper layer 13. In this way at least part of the surface of the membrane module is protected against contact with the fluid to be analysed.
  • the upper layer is not permeable to the two fluids .
  • a small opening 14 in the upper layer 13 provides a contact surface between the membrane module and the fluid to be analysed, so as to make analysis possible .
  • the upper layer to be applied on the membrane module may be provided with this opening beforehand, but it is also possible to apply an upper layer on the membrane module and to provide an opening afterwards .
  • the opening in the upper layer may be provided approximately in the middle of the membrane module, but a more lateral position is also possible . It is also possible to provide several openings in the upper layer. It is then necessary to ensure that reference fluid 4 is able to flow from the chamber 3 through the membrane module 6 into the fluid to be analysed. Due to the reduction of the flow-through surface of the membrane module, and hence of the exchanging surface, it is possible to perform a more accurate measurement than with a membrane module that is not covered.
  • the size of the opening is preferably smaller than 5 mm 2 , more preferably smaller than 2 mm 2 , and still more preferably smaller than 1 mm 2 , and even still more preferably smaller than 0.2 mm 2 . This also allows a substantial reduction of the flow rate of the reference fluid to the fluid to be analysed, so that there is less effect on the fluid to be analysed.
  • An additional advantage is that the reference electrode itself may be very robust while providing a very accurate measurement .
  • AKP stands for a registered trademark of the Sumitomo Company (Japan) .
  • the diameter of the particles mentioned relates to at least 99% of the total of particles present . All these particles are found in the range mentioned in the next column. The last column gives the pore size to be obtained with ideal packing.
  • Fig . 5 shows a test result obtained with a reference electrode according to the present invention, wherein measurement commences at point A; at point B fresh refer- ence fluid was fed into the storage vessel 9 , the composition differing somewhat from the original reference fluid.
  • the signal measured from point B therefore differs somewhat from the signal measured before .
  • the 25 days ' duration of the test virtually no variation was observed in the measured signal .
  • the ceramic material consisted of particles of ceramic aluminium oxide, type AKP 50 (obtainable from the Sumitomo company in Japan) , the ceramic particles having a diameter of 200 nm (99%) and a pore size of 50-70 nm.
  • the thickness of the membrane module was 1.5 mm.
  • the flow-through surface of the membrane was 35 mm 2 .
  • the overpressure generated by the micropump 8 was 2-4 bars .
  • the resulting flow rate was 0.5 to 4 microlitres per minute .
  • the reference fluid was comprised of a liquid having a 0.1 molar KCl and 0.1 molar KNO 3 concentration.
  • Fig. 6 shows a test result of a reference electrode according to the present invention . It can be clearly seen that during the period of 12 days of testing no variation in the measured signal was observed.
  • the ceramic material consisted of particles of ceramic aluminium ox- ide, type AKP 50 (obtainable from the Sumitomo company in Japan) .
  • the ceramic particles had a diameter of 200 nm ( 99%) and a pore size of 50-70 nm.
  • the thickness of the membrane module was 1.5 mm.
  • the flow-through surface of the membrane was in this case reduced to less than 0.1 mm 2 .
  • the overpressure generated by the micropump 8 varied from 1 to 4 bars .
  • the flow rate thus obtained was 3 microlitre per hour .
  • the reference fluid was a fluid of a 3 molar KCl concentration.
  • the flow rate may be further reduced by using a ceramic material wherein the ceramic particles used for the fabrication of a ceramic membrane module have a smaller diameter .
  • AKP 70 or a similar starting composition may be used.
  • the pressure which as described above and shown in Fig . 1 is supplied by a pump 8 , may also be generated by a compressed gas .
  • the gas may be stored in a gas storage container and may be connected with the chamber 3 via a pipe and a control valve .
  • the gas storage container may be connected with the storage vessel 9 via a control valve, in which case the pump 8 may be dispensed with .
  • the control valve may then be positioned between the vessel 9 and the chamber 3. All the variations on this theme lie within the scope of a person skilled in the art .

Landscapes

  • 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)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

L’invention concerne une électrode de référence (1) comprenant un module à membrane céramique (6), caractérisée en ce que le module à membrane céramique (6) est constitué de particules céramiques partiellement interconnectées formant une membrane poreuse, les particules ont un diamètre sensiblement identique de X nm, X est compris entre 40 et 450 nm, et de préférence 60% des particules, de préférence au moins 75%, plus préférablement au moins 90% et encore plus préférablement au moins 99%, ont un diamètre compris entre 0,9 * X et 1,1 * X, de préférence compris entre 0,95 * X et 1,05 * X, plus préférablement encore compris entre 0,99 * X et 1,01 * X.
PCT/NL2006/000071 2005-02-14 2006-02-13 Électrode de référence, module à membrane pour utilisation dans celle-ci et procédé de fabrication de celle-ci WO2006085761A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1028264A NL1028264C2 (nl) 2005-02-14 2005-02-14 Membraanmodule voor toepassing in een referentie-elektrode, een referentie-elektrode en werkwijze voor het vervaardigen van een membraanmodule.
NL1028264 2005-02-14

Publications (1)

Publication Number Publication Date
WO2006085761A1 true WO2006085761A1 (fr) 2006-08-17

Family

ID=34981673

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL2006/000071 WO2006085761A1 (fr) 2005-02-14 2006-02-13 Électrode de référence, module à membrane pour utilisation dans celle-ci et procédé de fabrication de celle-ci

Country Status (2)

Country Link
NL (1) NL1028264C2 (fr)
WO (1) WO2006085761A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009000315A1 (de) * 2009-01-20 2010-08-19 Robert Bosch Gmbh Flüssigkeitssensor

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB729575A (en) * 1952-09-03 1955-05-11 Jackson Jacob Improvements relating to reference electrode units
US2925370A (en) * 1958-06-13 1960-02-16 Beckman Instruments Inc Electrochemical leak structure and method for producing same
US4575410A (en) * 1982-03-11 1986-03-11 Beckman Industrial Corporation Solid state electrode system for measuring pH
US5071537A (en) * 1986-07-10 1991-12-10 Terumo Kabushiki Kaisha Reference electrode
NL1014256C2 (nl) * 2000-02-01 2001-08-14 Hydrion B V Meetinstrument geschikt voor het meten van kationen of anionen en membraam als onderdeel van het meetinstrument.
GB2370646A (en) * 2000-10-31 2002-07-03 Zeiss Stiftung Electrochemical measuring device
FR2843960A1 (fr) * 2002-08-29 2004-03-05 Centre Nat Rech Scient Ceramique a structure perovskite, son utilisation comme electrode de reference
DE10305005A1 (de) * 2003-02-07 2004-08-19 Kurt-Schwabe-Institut für Meß- und Sensortechnik e.V. Referenzelektrode
EP1491519A1 (fr) * 2003-06-25 2004-12-29 Mettler-Toledo GmbH Procédé de traitement de céramiques poreuses

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB729575A (en) * 1952-09-03 1955-05-11 Jackson Jacob Improvements relating to reference electrode units
US2925370A (en) * 1958-06-13 1960-02-16 Beckman Instruments Inc Electrochemical leak structure and method for producing same
US4575410A (en) * 1982-03-11 1986-03-11 Beckman Industrial Corporation Solid state electrode system for measuring pH
US5071537A (en) * 1986-07-10 1991-12-10 Terumo Kabushiki Kaisha Reference electrode
NL1014256C2 (nl) * 2000-02-01 2001-08-14 Hydrion B V Meetinstrument geschikt voor het meten van kationen of anionen en membraam als onderdeel van het meetinstrument.
GB2370646A (en) * 2000-10-31 2002-07-03 Zeiss Stiftung Electrochemical measuring device
FR2843960A1 (fr) * 2002-08-29 2004-03-05 Centre Nat Rech Scient Ceramique a structure perovskite, son utilisation comme electrode de reference
DE10305005A1 (de) * 2003-02-07 2004-08-19 Kurt-Schwabe-Institut für Meß- und Sensortechnik e.V. Referenzelektrode
EP1491519A1 (fr) * 2003-06-25 2004-12-29 Mettler-Toledo GmbH Procédé de traitement de céramiques poreuses

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009000315A1 (de) * 2009-01-20 2010-08-19 Robert Bosch Gmbh Flüssigkeitssensor

Also Published As

Publication number Publication date
NL1028264C2 (nl) 2006-08-15

Similar Documents

Publication Publication Date Title
US9447781B2 (en) Osmotically driven dispense pump and related components for use in high pressure applications
US5005403A (en) Process and apparatus for the determination of the concentration of a substance dissolved in a solvent by means of an osmometer
US10400759B2 (en) Flow sensors with modular microfluidic channels and methods of manufacture
JP4399455B2 (ja) 浸透変化の生体内測定センサ
JP2004518126A (ja) 微小流体流動性液絡部を有する新規基準電極
JP2013543447A (ja) 微小流体デバイス、微小流体注入システム、および微小流体のフロー測定と注入の方法
US20180093263A1 (en) Devices, Systems, and Methods for Dispensing and Analyzing Particles
RU2009141356A (ru) Устройство для перорального применения вещества
US10974039B2 (en) Method for the manufacturing of a carrying device, carrying device, system for detection of a physical parameter and method for detection of a physical parameter
EP2015801A2 (fr) Micro-pompe comprenant au moins un matériau émettant du gaz
WO2011137454A1 (fr) Détermination de la dimension de pores de matières poreuses par perte de masse par évaporation
WO2006085761A1 (fr) Électrode de référence, module à membrane pour utilisation dans celle-ci et procédé de fabrication de celle-ci
US10677622B2 (en) System for measuring flow of a liquid in a microfluidic circuit by determining gas and liquid pressures
JP3845067B2 (ja) 多孔質濾過体の細孔径測定方法
EP1413529A1 (fr) Soupape de dosage ajustable permettant de distribuer des liquides sous pression
CA2516724A1 (fr) Dispositif d'arret capillaire
EP3405762B1 (fr) Capteur de pression de fluide et son utilisation
Toker Improvements and reliability of MIT tensiometers and studies on soil moisture characteristic curves
JP2007533443A (ja) 接線流れ濾過のための、変化のある気孔率を有する支持体および膜
US7040141B2 (en) Capillary condensation method and apparatus for determining porosity characteristics of a sample
US20090117170A1 (en) Segmented device for the delayed release of molecules in a tangential direction through thin films and uses thereof
Smith et al. A system to measure minute hydraulic permeability of nanometer scale devices in a non-destructive manner
EP3752221B1 (fr) Dispositifs et procedes de restriction de flux dans un circuit microfluidique pour l'administration de medicament
JPS63200052A (ja) 界面電位測定装置
SU910926A1 (ru) Устройство дл контрол степени уплотнени грунта

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
DPE2 Request for preliminary examination filed before expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC, EPO FORM 1205A DATED 18.01.2008)

122 Ep: pct application non-entry in european phase

Ref document number: 06716614

Country of ref document: EP

Kind code of ref document: A1