JPS62239049A - Ion activity measuring instrument - Google Patents

Abstract

PURPOSE:To measure ion activity with high accuracy by forming liquid distributing members of non-woven fabrics of long fiber cellulose and setting the distance between said members and ion selective electrodes at a specific distance or below, then supplying a measuring liquid to the electrodes. CONSTITUTION:A water impermeable member 30 is provided on the ion selective electrode pairs 261-263 and the liquid distributing members 321, 322 made of the non-woven fabrics of the long fiber cellulose are provided. A sample liquid is spotted from a spotting hole 361 of an upper cap 35 and a reference liquid from a spotting hole 362, respectively and the respective liquids are distributed by the liquid distributing members 321, 322. The measuring liquid is then passed through a liquid supplying hole 312, etc., and is penetrated to the surface of the ion selective electrode 262. The distance at which the measuring liquid from the liquid distributing members 321, 322 arrives at the ion selective electrode 262 is set at <=6mm. The potential difference between both terminals 272 and 275 of the ion selective electrode is measured and the ion activity in the measuring liquid is measured. The liquid distributing members are made of the cellulose and the distance thereof from the ion selective electrodes the hemolysis of blood cells is prevented and the ion activity and more particularly potassium ion activity is measured with high accuracy.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the method of measuring the activity (or concentration) of a specific ion in an aqueous liquid, particularly a biological body fluid (blood, urine, saliva, etc.) using potentiometry. This invention relates to an ion activity measuring instrument for quantitative analysis.

[Background of the invention] The activity of specific ions contained in the droplets of liquids (tap water, river water, sewage, industrial wastewater, etc.) and biological fluids (blood, urine, saliva, etc.) is used to calculate the activity of specific ions contained therein. A method of measuring using a C+-shaped ion activity measuring instrument is already known.

That is, a reference liquid and a test liquid are applied to the ion-selective layer surface of each of a pair of ion-selective electrodes that are electrically separated from each other, and then each ion is This method measures the ionic activity of the test liquid by measuring the potential difference between selected electrodes. Examples of such ion activity measurement instruments include:
Ion activity measuring instruments described in JP-A-52-142586, JP-A-58-6148, JP-A-58-211648, and the like can be mentioned.

These ion activity measuring instruments basically have a pair of sheet-shaped ion-selective electrodes arranged with the ion-selective electrode facing upward, and a liquid spotting hole (for application of standard solution and test solution) on top of the ion-selective electrode. The reference solution and test solution are applied from above onto each ion-selective layer using a pipette or the like through the liquid spotting hole, and the sample solution is applied between both ion-selective electrodes. The ionic activity is measured by measuring the potential difference. On the other hand, by incorporating multiple ion-selective electrode pairs into one ion activity measurement device, it is possible to measure the activities of multiple types of ions by applying a reference solution and a test solution once each. The thing is Japanese Patent Publication No. 58-211648
Known by the number.

Although the method of measuring the ion activities of a plurality of types at the same time using a plurality of pairs of shear-shaped ion-selective electrodes as described above is a simple and excellent method, it has been found that there are the following problems.

In other words, when measuring ion activity, especially potassium ion activity, in whole blood, whole blood dilution, or similar blood samples containing blood cells (especially red blood cells), the blood sample may be hemolyzed in the ion activity measurement device. This caused the measured potassium ion activity to often differ from the true potassium ion activity in the blood sample. This was detected as a discrepancy with the potassium ion activity measured in plasma obtained by removing blood cells from the same blood sample. When a topical bandage, filter paper, or the like is used as a porous liquid distribution member, errors due to such hemolysis are large.

It takes some time for the measurement liquid (sample liquid, reference liquid) to permeate into the liquid distribution member and reach the surface of each ion selection electrode, making it possible to measure the potential difference. The hemolysis is exacerbated by the longer this time and by the greater the amount (surface area) of the liquid distribution member in contact with the whole blood. Synthetic polymer fibers, such as polyester fiber cloth, are materials that are relatively resistant to hemolysis of whole blood, but because the liquid develops slowly, potassium ion activity and other ion activities can be determined using - When used as a liquid distribution member in an ion activity measurement device for simultaneous measurement of ion activity, it takes time for the liquid to develop, and there is a risk of hemolysis.

For the liquid distribution member that supplies liquid to the potassium ion selective electrode, it is necessary to consider not only the material but also the arrangement and structure to prevent hemolysis.

The above-mentioned hemolysis problem occurred not only with the liquid distribution member, but also with the porous bridge for achieving electrical continuity between the sample liquid and the reference liquid. That is, when a bridge made of filter paper or gauze is used, hemolysis occurs strongly when whole blood is used as a sample liquid, causing a large error in the measurement results of potassium ion activity.

[Objectives of the Invention] The objects of the present invention are to shorten the time until stable potential measurement is possible after applying a sample solution or reference solution, to prevent the effects of hemolysis of blood, and to reduce the amount of ions in whole blood samples. An object of the present invention is to provide an ion activity measuring instrument particularly suitable for measuring activity.

[Structure of the Invention] The above object of the present invention is to provide an ion activity measuring instrument equipped with a porous liquid distribution member for supplying a sample liquid and a reference liquid to an ion selective electrode. A non-woven fabric consisting of the liquid distribution member is used as the liquid distribution member, and the structure is such that at least the sample liquid is supplied from the end portion or the side surface of the cut portion of the liquid distribution member, and the potassium ion selection electrode of the ion selection electrode is The shortest distance from the end to which the sample liquid is supplied or the side surface of the cutting part to the area of the electrode that comes into contact with the measurement liquid is 6.
The distance from the side surface of the end or cut portion to which at least the sample liquid is supplied of the porous liquid distribution member that supplies the liquid to the potassium potassium selection electrode is at least 8 mm, and the distance is at least 8 mm; This was achieved by using natural or synthetic fiber threads as bridges that electrically conduct the reference and sample solutions with each other.

a porous liquid distribution member that supplies liquid to the potassium selective electrode;
It is more preferable that the shortest distance from the end to which the sample liquid is supplied or the side surface of the cut section to the region of the potassium ion selective electrode that comes into contact with the sample liquid does not exceed 5 mm. It is more preferable that the distance from the side surface of the end to which the sample liquid is supplied or the cut part of the porous liquid distribution member that supplies the liquid to the potassium selection electrode to the other end is 10 mm or more.

The nonwoven fabric made of long fiber cellulose used in the liquid distribution member is preferably a cellulose spunbond nonwoven fabric that does not substantially contain a binder, and particularly preferably one made of long fibers made from cotton linters. For example, a nonwoven fabric manufactured by a spunbond method from a spinning solution obtained by dissolving cotton linters in Schweitzer liquid is preferred.

Such nonwoven fabrics are generally capable of absorbing at least 10 times the weight of the component in blood in 3 seconds.

The thickness of the porous liquid distribution member used in the present invention is approximately 1,000
11 to 400 meters is appropriate.

Natural fiber threads used for the bridge include cotton, silk, etc.
As the synthetic fiber, threads of polyester, polyamide (eg, nylon), etc. can be used.

The porous liquid distribution member used in the present invention is disclosed in Japanese Patent Application No. 59-2
44.200 may also be used.

Although the ion activity measuring instrument of the present invention can take various specific embodiments, it can also have a structure as shown in FIG. 1, for example. In the figure, 101°102, 1.03
is a pair of sheet-like solid electrodes having an ion-selective layer on the bottom surface, 4
00 has a spotting hole 410 and 420, and a frame body that accommodates a plurality of solid electrode pairs; 600 has a spotting hole 410 and 4;
20 is a porous bridge made of natural or synthetic fiber yarn, such as polyester yarn, and 200 is a water-impermeable member provided in contact with the lower surface of the ion-selective layer of the solid electrode pair. The sexual member 200 has a hole 210 as a liquid receiver.
, 220 and liquid supply hole 213, 223, 212, 2
22.2], 1. ．． 22] is provided. 312 and 311 are porous members that distribute liquid to the liquid supply holes 213 and 21.2, 211, respectively; 322 and 321;
500 is a porous member that distributes liquid to the liquid supply holes 223 and 222, 221, respectively; 500 is a lower frame body;
0 and 520 contain porous liquid distribution members 312 and 311 and 322 and 321, respectively. In the present invention,
The length of the porous member 311 (or 321) that supplies liquid to the potassium ion selective electrode pair 102 is at least 8
mm, preferably 10 mm or more, and the liquid receiver has a hole 210 (
or 220) facing the porous member 311 (or 321)
) is characterized in that the shortest distance from the end of the potassium ion selective electrode pair 102 to the liquid supply hole 212 is 6 mm or less, preferably 5 m or less. Lower frame body 50
0 has air vent holes 532, 531. , 542° 541 are provided. The porous bridge 600 may pass through an eccentric position from the center point of the liquid supply hole. In addition, the porous bridge 600 has −
It is preferable that it be provided in close contact with the upper surface of the frame body 400.

Further, the structure described in Japanese Patent Application Laid-Open No. 58-211.648 can be used. For example, as shown in FIG. 3, a sheet-like solid electrode pair 261 having ion-selective layers on two sides
．． 262.263, electrical connection terminal section 271. ．． 274
, 272, 275; 273° 276, a support frame 28 that accommodates a plurality of solid electrode pairs, a water-impermeable sheet member 30 that covers the surface of the solid electrode pairs, and three pairs of liquids provided on the water-impermeable member 30. Supply hole 311, . 3], 4.31.2, 315
．． 313, 31.6, liquid supply hole 311, 31.2, 31
．． Porous member 321 that distributes liquid to 3, liquid supply hole 314
, 315.31-6;
Two liquid storage tanks 3 each receiving a test liquid and a reference liquid.
41 and 342, spotting holes 361, 362 and air vent holes 371, . 372,373.374
, a porous bridge 38 of natural or synthetic fiber thread communicating between the spotting holes 361 and 362 is provided. The porous member 321 has liquid spotting holes 361 to liquid supply holes 31.1, 3.
1.2, 31.3, and the porous member 322 distributes the liquid from the liquid spotting hole 362 to the liquid supply holes 314, 315, 316.

JP-A-60-155960, JP-A-60-26084
The structure described in No. 3 and Japanese Patent Application Laid-open No. 60-260844 can also be used.

The ion activity measuring instrument of the present invention is also disclosed in Japanese Patent Application No. 60-18
No. 0358, Patent Application No. 180359, Patent Application No. 1983
It is also possible to have a structure as described in Japanese Patent No. 180360.

To measure ion activity using these ion activity measurement instruments, for example, three ion-selective electrode pairs are each
One pair is a potassium ion selective electrode pair, and the other is a sodium and chlorine ion selective electrode pair. When the reference solution and the test solution are applied to the liquid spotting holes, the reference solution and the test solution are porous liquids. The liquid permeates the distribution member and is supplied to the surface of each ion-selective electrode via liquid supply holes provided in the water-impermeable member. As a result, a potential difference is generated between the pair of ion-selective electrodes, and the potential difference can be measured with a potentiometer via the electrical connection terminal regions provided at both ends of the pair of ion-selective electrodes.

As a solid ion selective electrode, Japanese Patent Application Laid-Open No. 58-21164
No. 8, JP-A-60-237351, JP-A-60-23
No. 7352, JP-A-61-7460, JP-A-61. −
No. 7461, Japanese Patent Application Publication No. 1983-7462, Patent Application No. 1987-2
The ion selective electrode described in No. 32306 can be used.

Ion selective electrodes are disclosed in JP-A-58-102146, JP-A-58-1.56848, and JP-A-60-243555.
It can be manufactured by the method described in No.

[Effects of the Invention] In the present invention, a nonwoven fabric made of long-fiber cellulose made from cotton linters is used as the liquid distribution member, and the length of the porous member that supplies the sample liquid to the potassium ion selective electrode pair is adjusted. The minimum distance from one end of the porous member facing the liquid supply site to the area that contacts the potassium ion selective electrode pair (for example, liquid supply hole) must be 6 mm or less, and the reference liquid and sample liquid must be electrically connected to each other. Hemolysis during ion activity measurement can be avoided by using natural or synthetic fiber threads as bridges that electrically conduct the reference solution and sample solution, and by using natural or synthetic fiber threads as bridges that electrically conduct the reference solution and sample solution with each other. In particular, the influence on potassium ion activity measurement can be avoided.
In addition, when measuring ion activity, stable potential measurement can be performed in a short time after liquid spotting. By providing a natural or synthetic fiber thread that serves as a bridge to electrically conduct the reference liquid and sample liquid to each other, in close contact with the surface of the frame body that fixes the thread, in the middle of the area in contact with the reference liquid and sample liquid. , the potential measurement becomes more stable.

=12- Below, the present invention will be explained in more detail with reference to Examples.

[Example] (1) Production of Ag/AgCf electrode 180 micron thick polyethylene terephthalate (P
A continuous deposited film was prepared by depositing a silver layer of 8,000 layers on a film (ET), and the film was cut to a width of 24 mm. A groove with a depth of 70 microns was cut in the center of the film in the width direction using the tip of a knife. In addition, a 3 mm wide polyvinyl chloride toluene-methyl ethyl getone mixed solvent solution (removable film-forming mask resist) was applied to both ends.
It was dried and provided with a 30 micron thick protective film. Hydrochloric acid 60
m-mol/1, potassium dichromate 12 m-mol/
After being immersed for 90 seconds at 30° C. in an oxidation halogenation treatment solution containing f, the electrode was washed with water and dried to produce a sheet-like Ag/AgCJ electrode.

(2) Preparation of sodium ion selective electrode A solution having the following composition was applied onto the Ag/Ag (1!) electrode and dried.

Sodium chloride 6g Water 50g Ethanol 40g Thereafter, a solution having the following composition was applied so that the dry film thickness was approximately 5 microns.

Polymerization ratio of vinyl chloride vinyl acetate copolymer = 90:10 0.9 g (VYNS manufactured by Union Carbide) Dioctyl sebacate 1.2 g Methylmonensin o, i g Sodium tetraphenylporate 0.0021? Methyl ethyl ketone
5.0g surfactant 1% o, oeg
(5H510 manufactured by Shin-Etsu Chemical Co., Ltd.) Next, the resist layers applied to both ends were gently peeled off to expose the silver-deposited surfaces as electrical connection terminals.

This was cut into a width of 5 mm and used as a sodium ion selective electrode.

(3) Preparation of potassium ion selective electrode: Apply a solution with the following composition onto the Ag/AgC1 electrode,
Dry.

Sodium chloride 2.78 g Potassium chloride 2.22 g N-propyl alcohol 32 g Water 968 Surfactant 1% 0.06 [1 (SH51, O manufactured by Shin-Etsu Chemical Co., Ltd.) On top of this, a solution with the following composition was applied to a dry film. It was coated to a thickness of 30 microns, and the resist layers at both ends were peeled off to complete a potassium ion selective electrode.

Polymerization ratio of vinyl chloride vinyl acetate copolymer -90:10 0.9 g (VYNS manufactured by Union Carbide) Dioctyl phthalate 2.4 g Palinomycin 44 mB Potassium tetrakis-parachlorophenylborate 6 8 Methyl ethyl chemistries 5. Og surfactant 1% 0.05g (Shin-Etsu Chemical S H
510> = 15- (4) Preparation of chloride ion selective electrode A chloride ion selective electrode was prepared by coating the Ag/AgCN electrode to a dry film thickness of 12 microns, and peeling off the resist layers at both ends.

Polyvinyl butyral 1.0g trioctylmethylammonium chloride 1.0g ethanol
7.0 g surfactant 1%
0.04g (manufactured by Shin-Etsu Chemical 5H510) (5) Assembling the ion activity measuring device As shown in the exploded view in Figure 1, one set of liquid spotting holes 41.0.420 each with a diameter of 4 mm and two sets of Air vent hole 431,4
32.441,442 length 28mm, width 24m
A liquid spotting hole 41.m is provided in the groove portion of the plastic frame 400.
0.420 and a sodium selective electrode 10 on one side.
3. Potassium ion selective electrode 102 on the other side. The chloride ion selective electrode 101 is housed in the direction in which the ion selective layer is exposed, and one set of liquid receivers has a hole 210.220 and three sets of liquid supply picture cards 21.3, 223.21.2, 222.21. 1. .

A double-sided adhesive tape 200 on which 221 was previously provided was attached to the electrodes and the surfaces of the frame so that each row of liquid supply holes faced each electrode surface. The liquid receiver is the hole 210 and the liquid supply hole 213.
, 212, and the distance between the centers of the liquid receiver hole 220 and the liquid supply holes 223, 222 are 5.
8 mm, and the distance between the centers of the liquid supply holes 212 and 211 and the distance between the centers of the liquid supply holes 222 and 22.1 were both 5.7 mm. - Next, a set of liquid distribution members 311 with a width of 2 mm and a length of 13 mm are made of Benliese G5303 manufactured by Asahi Kasei Corporation, which is a long fiber cellulose nonwoven fabric. ．． 321, and width 2mm,
Another set of liquid distribution members 312, 322 with a length of 7.3 mm
1 on the double-sided adhesive tape 200, and the liquid supply hole 21
One end was located at a distance of 1 mm from the center of 0 and 220, respectively, and was fixed 17 so as to cover each liquid supply hole. Furthermore, this polystyrene support frame 500 having two pairs of groove portions 510 and 520 is attached to the groove portions 510 and 520.
was attached so as to accommodate the liquid distribution member. The ion activity measurement device assembled in this manner is used with the liquid spotting hole facing upward.

Fig. 2A shows a cross-sectional view of the ion activity measuring device described in 1.
Fig. B shows an enlarged view of the portion indicated by X in Fig. 2A, and Fig. 2C shows a plan view of the ion activity measuring instrument shown in Fig. 1. Second
In Figure B, 102a is the film support of the potassium ion selective electrode, 102b is the silver layer, 102c is the silver chloride layer, 102
d indicates an electrolyte layer, and 102e indicates an ion-selective membrane layer.

(7) Potential measurement" The sample liquid supply hole of the ion activity measurement device prepared as described in 1.
A reference solution having the following composition is simultaneously applied to each of the reference solution supply holes, and the potential difference generated after 1 minute is determined from the terminals 113, 1.23.11.2, 122; 1. 1.
1,121 using an Orion Microprocessor Model 901 (manufactured by Orion). For comparison, potentials were measured in the same manner using plasma obtained from the same whole blood sample by centrifugation. Table 1 shows the potassium ion activity (average value) determined using a calibration curve from five measurements of the potential difference of the potassium ion selective electrode 1 minute after spotting.

Table 1

[Brief explanation of drawings]

FIG. 1 and FIG. 3 are exploded perspective views showing one embodiment of the ion activity measuring device of the present invention, respectively. Figure 2A is a cross-sectional view of the ion activity measuring device shown in Figure 1, Figure 2B is an enlarged view of the portion indicated by X in Figure 2A, and Figure 2C is a plan view of the ion activity measuring device shown in Figure 1. It is. Applicant: Fuji Photo Film Co., Ltd. Figure 2A Figure 2B Figure 2C

Claims (1)

[Claims] (1) a pair of ion-selective electrodes that selectively respond to specific ions, a porous liquid distribution member capable of supplying a test liquid to a first electrode of the pair of electrodes, and a second electrode of the pair of electrodes; An ion activity measuring device comprising a porous liquid distribution member capable of supplying a reference liquid to each electrode, and a porous bridge to achieve electrical continuity between the test liquid and the reference liquid supplied to each electrode. The liquid distribution member is a nonwoven fabric made of long-fiber cellulose, and the liquid distribution member has a structure in which at least a sample liquid is supplied from an end or a side surface of a cut portion of the liquid distribution member at a liquid supply portion. In particular, when the ion-selective electrode is a potassium ion-selective electrode, the shortest distance from the end of the porous liquid distribution member to which the sample liquid is supplied or the side surface of the cut portion to the area of the electrode that contacts the measurement liquid. the electrode is provided at a position that does not exceed 6 mm; An ion activity measuring device characterized in that the distance is at least 8 mm, and a natural or synthetic fiber thread is used as a bridge to electrically conduct the reference liquid and the sample liquid to each other.