JP2006192032A - Transdermal blood gas sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transdermal blood gas sensor which reduces the amount of a material used for an electrode. <P>SOLUTION: The transdermal blood gas sensor has a main body 110 of the sensor and an electrode unit 120 mounted on the main body 110. The electrode unit 120 has a permeable membrane 121 for a gas subjected to measurement, an impermeable member 122 for the gas, an electrolytic solution 123 retained between them, and membraneous one and the other electrodes capable of measuring the concentration of the gas subjected to the measurement in the electrolytic solution as electric signals. The amount of the expensive material used for the electrode is reduced since the membraneous electrodes are used by retaining the electrolytic solution 123 between the permeable membrane 121 and the impermeable member 122 and by adding a function as the electrode between both membranes 121, 122. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a percutaneous blood gas sensor for measuring oxygen partial pressure, carbon dioxide partial pressure, etc. in blood from the surface of the skin, and an electrode unit for the sensor. In particular, the present invention relates to a transdermal blood gas sensor that can reduce the amount of electrode material used and achieve downsizing and cost reduction.

  For example, a sensor described in Patent Document 1 is known as a technique for measuring oxygen partial pressure or carbon dioxide partial pressure in blood for respiratory management of neonates or critically ill patients who require artificial respiration. This sensor utilizes the fact that an amount of gas proportional to the gas partial pressure outside the sensor dissolves in the electrolyte solution through the sensor membrane, and the amount of dissolved gas correlates with the current value and potential generated at each measurement electrode. It is a sensor that measures the gas partial pressure.

As shown in FIG. 4, the sensor 200 includes a sensor main body 210, a membrane holder 220, and a ring-shaped collar 230. The sensor main body 210 includes an O ₂ measuring cathode 211, a CO ₂ measuring pH electrode 212, a heater 213, and a thermistor 214, and these members are held by a silver electrode 215. The silver electrode 215 also serves as an anode for O ₂ measurement, a reference electrode for CO ₂ measurement, and a heating body, and the measurement side surface is covered with silver chloride. The silver electrode 215 as the heating body is heated by the heater 213, the temperature of the silver electrode 215 is measured by the thermistor 214, and the temperature is adjusted by controlling the energization amount to the heater 213 based on the measurement result. . Furthermore, an amplifier 216 that amplifies the measurement signal of the pH electrode 212 is also built in the sensor body 210.

  On the other hand, the membrane holder 220 is positioned between the ring-shaped collar 230 and the sensor body 210, and is attached to the sensor body 210 by screwing the ring-shaped collar 230 into the sensor body 210. In addition, a membrane 240 that transmits the measurement target gas is sandwiched between the membrane holder 220 and the ring-shaped collar 230, and the electrolytic solution 250 is held between the lower surface of the sensor body 210 and the membrane 240.

  For example, when the oxygen partial pressure in blood is measured with this sensor, the silver electrode 215 is heated to a predetermined temperature by the heater 213, and the membrane 240 is brought into contact with the skin. The oxygen in the subcutaneous tissue warmed by the heat from the heater 213 diffuses from the skin surface, permeates through the membrane 240, and is dissolved in the electrolytic solution 250. For example, when a constant voltage is applied between the cathode and the anode, a current corresponding to the amount of dissolved oxygen flows. Therefore, the oxygen concentration in the blood can be obtained by measuring this current, and the oxygen concentration can be determined from the oxygen concentration. The pressure can be measured.

Japanese Patent Publication No. 7-51126

  However, the above sensor has the following problems.

(1) A lot of electrode materials must be used.
As is clear from the above explanation, the anode for O ₂ measurement, the reference electrode for CO ₂ measurement, and the silver electrode that also serves as a heating element are relatively large blocks, and expensive silver must be used frequently. As a result, the product cost is increased.

(2) The replacement work of the electrolyte and membrane is complicated.
The electrolyte solution and the membrane need to be replaced regularly. However, in the above sensor, the ring collar is removed, the membrane must be replaced, and the electrolyte solution must be filled. Especially, in order to prevent unstable measurement sensitivity, the membrane should be mounted so as not to have a non-uniform tension, or a certain amount of electrolyte should be filled accurately, and the distance between the membrane and the sensor body should be uniform. Thus, it is not always easy to perform the replacement work.

(3) Periodic electrode maintenance is required.
In the conventional sensor described above, each electrode must be regularly maintained in order to keep its performance good. Specifically, in the O ₂ electrode, it is necessary to polish and remove silver that gradually adheres to the anode (gold or platinum) by an electrode reaction. In addition, since the silver chloride on the silver surface is easily peeled off at the CO ₂ electrode, it is necessary to coat the silver chloride again.

  The present invention has been made in view of the above circumstances, and its main object is to provide a transdermal blood gas sensor capable of reducing the amount of electrode material used.

  Another object of the present invention is to provide a transcutaneous blood gas sensor in which an electrode unit can be easily replaced and no electrode maintenance is required.

  Furthermore, another object of the present invention is to provide an electrode unit having an electrode function capable of measuring the concentration of the measurement target gas as an electric signal.

  The present invention achieves the above object by using a thin unit holding an electrolytic solution between a permeable membrane for a gas to be measured and a non-permeable member and providing the unit with an electrode function.

  The transdermal blood gas sensor of the present invention has a sensor body and an electrode unit attached to the sensor body. The electrode unit is configured to measure the concentration of the measurement target gas in the electrolyte, the permeable membrane of the measurement target gas, the non-permeable member of the same gas, the electrolytic solution held between the permeable membrane and the non-permeable member. It has the thin film-like one electrode and other electrode which can be measured as an electric signal.

  In addition, the electrode unit of the present invention includes a permeable membrane of a measurement target gas, a non-permeable member of the same gas, an electrolytic solution held between the permeable membrane and the non-permeable member, and a concentration of the measurement target gas in the electrolytic solution. It has the thin film-like one electrode and other electrode which can be measured as an electric signal.

  The sensor of the present invention holds the electrolyte solution between the permeable membrane of the gas to be measured and the non-permeable member, and adds an electrode function between the permeable membrane and the non-permeable member, so that the thin-film electrode is formed. It can be used, and the amount of expensive electrode material used can be reduced.

  In addition, the permeable membrane of the measurement target gas and the electrolyte solution can be replaced very easily by simply attaching and detaching the electrode unit together with the sensor body.

  Hereinafter, the present invention will be described in more detail.

  The sensor of the present invention has a sensor body and an electrode unit. First, the structure of the electrode unit, which is the main feature of the present invention, will be described.

(Electrode unit)
The electrode unit has an electrode function capable of holding the electrolytic solution and extracting the measurement gas concentration in the electrolytic solution as an electrical signal.

<Permeation membrane>
The permeable membrane is a membrane through which the measurement target gas can pass, and may be appropriately selected according to the type of the measurement target gas. For example, a fluororesin or a polypropylene film can be used as the O ₂ or CO ₂ permeable membrane.

<Impermeable member>
The impervious member holds the electrolyte and electrode between the permeable membrane, and prevents measurement target gas from entering the electrolyte from the opposite side of the permeable membrane in the electrode unit and prevents evaporation of the electrolyte. It has a function that contributes to improving accuracy. For example, high-density polyester, ceramics, glass epoxy and the like can be used as O ₂ and CO ₂ impermeable members. A typical example of the form of the impermeable membrane member is a film. However, even a resin piece or a ceramic piece with poor flexibility may be allowed to have a plate shape with a certain thickness as long as the heat conduction from the sensor body is not hindered. Usually, the impervious member is provided facing the sensor body side.

<Electrolyte>
The electrolyte solution may be any liquid that can dissolve the gas to be measured and can undergo an electrode reaction according to the dissolved amount of the gas. More specifically, a liquid mainly composed of KCl or NaCl for O ₂ and NaHCO ₃ as a main component for CO ₂ can be preferably used.

  This electrolytic solution does not need to exist over almost the entire surface between the permeable membrane and the non-permeable member, and it is sufficient that the electrolytic solution exists at least at a location where an electrode reaction between one electrode and the other electrode described later occurs.

<One electrode and the other electrode>
The one electrode and the other electrode may be an electrode pair that can extract an electrical signal in accordance with the dissolved amount of the measurement target gas in the electrolyte. In the present invention, since one electrode and the other electrode are disposed between the permeable membrane and the non-permeable member, these electrodes are in the form of a thin film.

More specifically, when the measurement target gas is O ₂ , from the viewpoint of measurement performance, one electrode is a cathode made of platinum or gold, and the other electrode is an anode made of silver or a composite material of silver and silver chloride; It is preferable to do. In that case, if a predetermined voltage is applied between both electrodes, an oxygen reduction reaction is performed at the cathode and a silver oxidation reaction is performed at the anode, and an electric field current flows between both electrodes, and the current is measured. Thus, the oxygen concentration in the electrolytic solution can be approximately measured. A typical example of a composite material of silver and silver chloride is silver coated with silver chloride.

When the measurement target gas is CO ₂ , it is preferable from the viewpoint of measurement performance that one electrode is an ion selective electrode and the other electrode is a comparative electrode made of silver chloride or a composite material of silver and silver chloride. An ion selective electrode is an electrode whose electrode potential changes in response to the concentration of specific ions present in the electrolyte. By using this ion selective electrode in combination with a comparative electrode, the concentration of specific ions is measured. The concentration of CO ₂ is passed through a permeable membrane CO ₂ dissolves in the electrolyte, pH becomes carbonate (hydrogen ion concentration) is measured by utilizing the change. More specifically, an ISFET (Ion Sensitive Field Effect Transistor) in which an ion selective electrode and a field effect transistor (FET) are integrated as an amplifier for amplification can be suitably used. A typical example of a composite material of silver and silver chloride is silver coated with silver chloride.

In addition, a plurality of types of electrode pairs may be arranged in one electrode unit so that a plurality of blood gas concentrations can be measured with one sensor. In this case, for example, an electrode pair for measuring O ₂ and an electrode pair for measuring CO ₂ are arranged in one electrode unit. In particular, since the same material can be used for the anode for measuring O ₂ and the reference electrode for measuring CO ₂ , it is preferable from the viewpoint of reducing the number of parts and materials used that these anode and reference electrode are shared. It is.

  The one electrode and the other electrode may be formed on the permeable membrane side or may be formed on the non-permeable member side.

<Signal terminal>
In addition, a signal terminal for transmitting an electrical signal from the electrode to the sensor body is usually provided. For example, a conductor pattern for transmitting signals from the electrodes may be formed between the permeable membrane and the non-permeable member, and the conductive member may be drawn out of the electrode unit from the conductor pattern to be a signal terminal. In this case, it is preferable that the signal terminal itself is an engaging portion for mounting the electrode unit on the sensor body.

  Of course, an engaging portion for mounting the electrode unit on the sensor body may be formed separately from the signal terminal. For example, a reinforcing ring portion that covers the outer peripheral portion of the electrode unit may be provided, and an engaging portion that engages with the housing of the sensor main body of the reinforcing ring portion may be formed separately from the signal terminal. In that case, it is possible to omit the use of a fixing ring described later.

(Sensor body)
On the other hand, the basic configuration of the sensor body can use the conventional configuration of a transdermal blood gas sensor. Typically, the sensor main body includes a housing, a heating unit, a heating body, and a temperature sensor.

<Housing>
The housing is a member corresponding to the cover of the sensor of the present invention. Usually, a container-like member having a resin-molded opening can be suitably used. The housing preferably has a receptacle into which the signal terminal of the electrode unit is inserted. The signal terminal is engaged with the receptacle so that the measurement signal of the sensor of the present invention can be output to the percutaneous blood gas measurement device via the sensor body. And in this housing, a heating means, a heating body, and a temperature sensor are accommodated.

<Heating means>
The heating means warms a heating body described below to a predetermined temperature, transfers the temperature to the skin, and efficiently diffuses the measurement target gas from the subcutaneous tissue to the skin surface. For example, a heater by energization heating can be suitably used.

<Heating body>
The member heated by the heating means is a heating body. The heat of the heating body is transmitted to the skin through the electrode unit. The heating body is preferably made of a material having heat resistance against being heated by the heating means and heat conductivity capable of quickly transferring the heat of the heating means.

Conventionally, since this heating element also functions as an anode for O ₂ measurement and a reference electrode for CO ₂ measurement, the electrode surface was composed of silver covered with silver chloride. In the present invention, the electrode for O ₂ measurement Since the CO ₂ measurement electrode pair is provided in the electrode unit, it is preferable to use a cheaper material for the heating element. More specifically, copper, aluminum, and white (a silver: Cu / Ni / Zn alloy) can be used.

  This heating element is usually fitted in the housing such that a part thereof is exposed from the opening of the housing. Then, the electrode unit is mounted facing the exposed surface of the heating body.

<Temperature sensor>
The temperature of the heating body is detected by a temperature sensor and adjusted by controlling the heating means based on the detection result. A semiconductor element such as a thermistor can be suitably used for the temperature sensor for this purpose.

<Amplification means>
In addition, amplification means may be provided in the sensor body as necessary. This amplification means amplifies the signal sent from the electrode of the electrode unit and outputs it to the transcutaneous blood gas measurement device.

(Fixing ring)
In addition, it is preferable to use a fixing ring that is engaged with the sensor body and fixes the electrode unit to the sensor body side. Typically, an annular member that can be attached to the outer periphery of the sensor main body by screwing and covers the peripheral portion of the electrode unit is exemplified.

  According to the sensor and the electrode unit of the present invention, the following effects can be obtained.

  (1) Use a thin-film electrode by holding the electrolyte between the permeable membrane of the gas to be measured and the non-permeable member and adding an electrode function between the permeable membrane and the non-permeable member. Can do. Therefore, the amount of expensive electrode material used can be reduced, and the product cost can be reduced.

  (2) Replacement of the permeable membrane or electrolyte for the gas to be measured can be performed very easily by simply attaching and detaching the electrode unit together with the sensor body. Therefore, it is possible to eliminate troublesome operations such as mounting a membrane that has been a problem in the past with uniform tension and making the thickness of the electrolyte layer uniform.

  (3) Since the electrode is protected by being sandwiched between the permeable membrane of the gas to be measured and the impermeable member, the electrode is not directly touched by hand, and the electrode may be soiled or damaged. Absent.

  (4) Since each electrode is replaced for each electrode unit, the sensor performance can be maintained in a good state without performing maintenance such as polishing the electrode or recoating silver chloride as in the past. .

Embodiments of the present invention will be described below. Here, a sensor for measuring the partial pressure of O ₂ and CO _{2 in} blood will be described as an example.

(Overall structure)
As shown in FIGS. 1 and 2, the sensor 100 of the present invention includes a sensor body 110, an electrode unit 120, and a fixing ring 130. Each of these components will be described in detail.

(Sensor body)
The sensor body 110 includes a housing 111, a heater 112, a heating body 113, a thermistor 114, and amplification means 115.

<Housing>
The housing 111 is a member corresponding to the cover of the sensor 100 of the present invention, and houses the heater 112, the heating body 113, and the thermistor 114 therein. Here, a plastic container 111 in the shape of a disk container having an upper part closed and a lower part opened is used. A male threaded portion 111A is formed on the outer peripheral surface of the opening side of the housing 111, and the fixing ring 130 is screwed into the electrode 111 to hold the electrode unit 120 between the sensor body 110 and the fixing ring 130.

  In addition, the housing 111 has a receptacle 111B formed on the end surface on the opening side. The receptacle 111B is for receiving a signal terminal 126 of an electrode unit, which will be described later, and electrically connecting each electrode pair, which will be described later.

<Heater>
The heater 112, which is a heating means, heats the heating element 113 described below to a predetermined temperature, transfers the temperature to the skin, and efficiently diffuses oxygen and carbon dioxide from the subcutaneous tissue to the skin surface. is there. Here, a heating wire is wound around the outer periphery of the heating body 113 to form the heater 112. The heater 112 is connected to a percutaneous blood gas measurement device (not shown) and receives power supply from the device.

<Heating body>
A member heated by the heater 112 is a heating body 113. The heat of the heating body 113 is transmitted to the skin through the electrode unit 120. Here, a cylindrical block-shaped copper heating element is used in which the outer diameter is larger toward the upper side and the diameter is gradually reduced toward the lower side. A mounting hole 113A of the thermistor 114 is formed on the upper surface of the heating body 113 so as to extend downward.

  The heating body 113 is fitted into the housing 111 so that the lower surface thereof is exposed from the opening of the housing 111. Then, the electrode unit 120 is mounted so as to face the exposed surface of the heating body 113.

<Thermistor>
The temperature of the heating element 113 is detected by the thermistor 114 as a temperature sensor, and is adjusted by controlling the heater 112 based on the detection result. The thermistor 114 is accommodated in the mounting hole 113A of the heating body 113. The thermistor 114 is connected to a percutaneous blood gas measuring device (not shown).

<Amplification means>
In the space formed between the housing 111 and the upper surface of the heating body 113, the amplifying means 115 is arranged. This amplifying means 115 amplifies the signal sent from the electrode of the electrode unit 120 and outputs it to a percutaneous blood gas measuring device (not shown).

(Electrode unit)
Next, the electrode unit 120 will be described. 3A shows a cross-sectional view of the electrode unit, and FIG. 3B shows a plan view thereof. The electrode unit 120 includes a permeable membrane 121, a non-permeable member 122, an electrolytic solution 123, an O ₂ measuring electrode pair 124, a CO ₂ measuring electrode pair 125, and a signal terminal 126. And an electrode function capable of extracting the measurement gas concentration in the electrolyte as an electrical signal.

<Permeation membrane>
The permeable membrane 121 is a membrane that allows the measurement target gas to pass therethrough. Here, a polypropylene film was used as the O ₂ and CO ₂ permeable membrane. The permeable membrane 121 is disposed on the lower surface side as shown in FIG. 1, and is in direct contact with the skin.

<Impermeable member>
The non-permeable member 122 holds the electrolytic solution 123 and the electrode pairs 124 and 125 between the permeable membrane 121, and the measurement target gas enters the electrolytic solution 122 from the opposite side of the permeable membrane 121 in the electrode unit 120. To prevent. Here, a high-density polyester film was used as the O ₂ and CO ₂ impermeable member 122. The impervious member 122 is provided facing the exposed surface of the heating body 113 in the sensor body 110.

<Electrolyte>
The electrolytic solution 123 is a liquid in which a measurement target gas can be dissolved and an electrode reaction can be performed according to the dissolved amount of the gas. Here, a liquid mainly composed of NaCl, NaHCO ₃ or the like is used. Further, the electrolytic solution 123 is held only in a part of the electrode unit 120. In this example, the electrolytic solution 123 is held only in the portion related to the electrode reaction of the electrode pair 124 for O ₂ measurement and the electrode pair 125 for CO ₂ measurement described below, that is, in the substantially central portion of the electrode unit 120. The portion where the electrolytic solution 123 is held partially forms a portion where the permeable membrane 121 and the non-permeable member 122 are not bonded, and the electrolytic solution 123 is interposed between the permeable membrane 121 and the non-permeable member 122 in that portion. It is configured by storing. In addition, in order to hold the electrolytic solution 123, a porous film may be used.

<O ₂ measurement electrode pair and CO ₂ measurement electrode pair>
In this example, an O ₂ measurement electrode pair and a CO ₂ measurement electrode pair are provided so that both O ₂ and CO ₂ can be measured by one sensor.

The O ₂ measuring electrode pair 124 includes a cathode 124A made of platinum and an anode 124B made of silver whose surface is covered with silver chloride. When a predetermined voltage is applied between the cathode 124A and the anode 124B, an oxygen reduction reaction is performed at the cathode 124A and a silver oxidation reaction is performed at the anode 124B, and an electric field current flows between both electrodes 124A and 124B. By measuring the current, the oxygen concentration in the electrolytic solution 123 can be approximately measured. In this example, an elongated thin-film cathode 124A extending from approximately the center of the electrode unit 120 to the outer peripheral side, and an anode 124B that is E-shaped and larger than the cathode 124A are disposed at approximately the center of the electrode unit 120. The tip of the cathode 124A is disposed so as to be fitted into one of the two concave portions of the E-type anode 124B, and a certain gap is secured from the anode 124B.

The CO ₂ measurement electrode pair 125 is composed of one electrode using an ISFET (Ion Sensitive Field Effect Transistor) 125A and a comparison electrode 125B made of silver whose surface is covered with silver chloride. The ISFET 125A is a semiconductor ion electrode in which an FET is integrated as an ion selective electrode and an amplifier for amplification. This ISFET 125A extracts the change in pH (hydrogen ion concentration) as CO ₂ passing through the permeable membrane 121 dissolves in the electrolyte 123 and becomes carbonic acid as a displacement of the electrode potential when used in combination with the reference electrode 125B. Measure the CO ₂ concentration. This ISFET 125A is arranged with a certain gap from the reference electrode 125B so as to be fitted into the remaining one of the two concave portions of the E-type reference electrode 125B (anode 124B), and extends to the outer peripheral side of the electrode unit 120. Pattern 127 is connected. The two conductive patterns 127 are arranged in parallel with the cathode 124A for measuring O ₂ .

The anode 124B for measuring O ₂ and the reference electrode 125B for measuring CO ₂ are made of a common material, so that the anode 124B and the reference electrode 125B are shared as a single unit. A single thin thin-film conductive pattern 128 is connected to the anode 124B (comparison electrode 125B). The conductive pattern 128 extends from the substantially central portion of the electrode unit 120 in the direction opposite to the cathode 124A and the conductive pattern 127 and reaches the outer peripheral edge.

<Signal terminal>
The electrode unit 120 is provided with a signal terminal 126 for transmitting electrical signals from the electrode pairs 124 and 125 to the sensor body side. In this example, one end of the anode 124B for measuring O ₂ , each end of the two conductive patterns 127 connected to the ISFET 125A, and a total of four ends of the conductive pattern 128 connected to the anode 124B (comparison electrode 125B). A signal terminal 126 is formed at each location. Each of these terminals 126 penetrates the opaque member 122 and protrudes toward the opaque member 122 (sensor body 110) side of the electrode unit. These terminals 126 are fitted into the above-described receptacle 111B of the housing 111, whereby electric signals from the electrode pairs 124 and 125 are transmitted to the sensor body side.

(Fixing ring)
When the electrode unit 120 is mounted on the sensor body 110, a fixing ring 130 is used to reliably press the electrode unit 120 against the sensor body 110 (see FIGS. 1 and 2). The fixing ring 130 includes an annular portion 131 and a thin ring-shaped pressing surface 132 projecting toward the inner peripheral side below the annular portion 131. Inside the annular portion 131, a female screw portion 131A to be screwed into the male screw portion 111A of the housing is formed.

  By attaching the electrode unit 120 to the sensor body 120 and further screwing the female screw part 131A of the fixing ring into the male screw part 111A of the housing, the peripheral part of the electrode unit 120 is sandwiched between the housing 111 by the pressing surface 132 . Since the lower surface of the heating body 113 protrudes downward from the outer peripheral end surface of the housing 111, the electrode unit 120 is pressed against the lower surface of the heating body 113 and held in a tensioned state with a certain tension.

(Function and effect)
According to the above-described sensor of the present invention, the electrolyte solution is held between the permeable membrane of the measurement target gas and the non-permeable member, and the electrode function is added between the two membranes, thereby using the thin film electrode. The amount of expensive electrode material used can be reduced.

  In addition, the permeable membrane of the measurement target gas and the electrolytic solution can be exchanged very easily by simply removing the fixing ring and attaching / detaching the electrode unit together with the sensor body.

  Furthermore, since the electrode is sandwiched and protected between the permeable membrane of the measurement target gas and the non-permeable member, the electrode is not directly touched by hand, and the electrode is not soiled or damaged. .

  In addition, since the electrodes are exchanged together with the electrode units, the maintenance of the electrodes that has been conventionally required becomes unnecessary.

  The sensor and electrode unit of the present invention can be used in the field of measuring oxygen partial pressure and carbon dioxide partial pressure in blood from above the skin. More specifically, it can be suitably used for respiratory management of newborns and critically ill patients who require artificial respiration.

It is a schematic cross section which shows the assembly state of this invention sensor. It is a schematic cross section which shows the decomposition | disassembly state of this invention sensor. (A) is a schematic cross section showing an electrode unit used in the sensor of the present invention, and FIG. (B) is a plan view of the same. It is a schematic cross section which shows the conventional sensor.

Explanation of symbols

100 sensors
110 Sensor body
111 Housing 112 Heater 113 Heating element 114 Thermistor
115 Amplifying means 111A Male thread 111B Receptacle 113A Mounting hole
120 electrode unit
121 permeable membrane 122 impermeable member 123 electrolyte 124 O ₂ electrode pair for measurement
125 CO ₂ electrode pair 124A cathode 124B anode 125A ISFET
125B Reference electrode 126 Signal terminal 127, 128 Conductive pattern
130 Retaining ring
131 Annular part 132 Pressing surface 131A Female thread part
200 sensors
210 Sensor body 220 Membrane holder 230 Ring collar
240 Membrane 250 Electrolyte
211 Cathode for O ₂ measurement 212 pH electrode for CO ₂ measurement 213 Heater
214 Thermistor 215 Silver electrode 216 Amplifier

Claims (6)

A sensor body;
An electrode unit mounted on the sensor body,
This electrode unit
A permeable membrane for the gas to be measured;
An impermeable member of the same gas;
An electrolyte solution held between the permeable membrane and the impermeable member;
A transcutaneous blood gas sensor comprising a thin film-like one electrode and the other electrode capable of measuring the concentration of a measurement target gas in an electrolyte as an electrical signal. The transcutaneous blood according to claim 1, wherein the measurement target gas is O ₂ , one electrode is a cathode made of platinum or gold, and the other electrode is an anode made of silver or a composite material of silver and silver chloride. Medium gas sensor. The transdermal blood according to claim 1, wherein the measurement target gas is CO ₂ , one electrode is an ion selective electrode, and the other electrode is a comparative electrode made of silver chloride or a composite material of silver and silver chloride. Medium gas sensor. The gas to be measured is O ₂ and CO ₂
One electrode for O ₂ measurement is a cathode made of platinum or gold, and the other electrode is an anode made of silver or a composite material of silver and silver chloride,
The transdermal blood gas sensor according to claim 1, wherein one electrode for measuring CO ₂ is an ion selective electrode, and the other electrode is a comparative electrode made of silver chloride or a composite material of silver and silver chloride. The transdermal blood gas sensor according to claim 4, wherein the anode for measuring O ₂ and the reference electrode for measuring CO ₂ are integrated. A permeable membrane for the gas to be measured;
An impermeable member of the same gas;
An electrolyte solution held between the permeable membrane and the impermeable member;
An electrode unit for a transdermal blood gas sensor, comprising a thin film-like one electrode and the other electrode capable of measuring the concentration of a measurement target gas in an electrolyte as an electrical signal.

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