JPH0476578B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to aqueous liquid samples such as alcoholic beverages, beverages,
The present invention relates to an ion activity measuring instrument for quantitatively analyzing the activity (or concentration) of a specific ion in tap water, particularly biological fluids (blood, urine, saliva, etc.) using potentiometry.

(Prior art) A slide-type ion activity measuring instrument that can spot a liquid sample and measure the activity of specific ions contained therein is disclosed in Japanese Patent Application Laid-open No. 58-211648 and Japanese Patent Application Laid-Open No. It is disclosed in No. 59-30055, JP-A-60-155960, etc.

Among these, the ion activity measurement device described in JP-A No. 58-211648 and JP-A No. 60-155960 has multiple sets of ion-selective layers in the outermost layer that selectively respond to specific ions. Pairs of selective electrodes are provided, the lower portions of these pairs of ion selective electrodes are fixed to a lower support frame, and the upper portion is a water impermeable electrode having at least one liquid receiving hole penetrating therethrough at a position corresponding to each of the ion selective electrodes. A pair of porous liquid distribution members made of cotton bandage cloth, polyester mesh, etc. are disposed on the water-impermeable material layer, and one ion-selective electrode of each of the plurality of ion-selective electrode pairs is disposed on the water-impermeable material layer. arranged so as to communicate each pair of liquid receiving holes provided at positions corresponding to
Furthermore, an upper frame having a pair of liquid supply holes (spotting holes) penetrating each of the pair of porous liquid distribution members is provided on the pair of porous liquid distribution members so as to be aligned with the lower support frame. There is. In addition, these ion activity measuring instruments have a method for achieving electrical continuity (liquid junction) between the sample liquid that is spotted into one of the pair of liquid spotting holes and the reference liquid that is spotted and supplied to the other of the pair of liquid spotting holes. A porous bridge (strand of fibers) is usually provided on the upper frame.

In the ion activity measuring instrument configured in this way, for example, if the plurality of ion-selective electrode pairs respond to Na, K, and Cl, for example,
A reference liquid with known activities of these ions is spotted on one of a pair of liquid spotting holes, and a sample liquid with unknown activities of said ions is spotted on the other. Both solutions are porous liquids. It penetrates the distribution member and reaches the corresponding ion-selective electrode via the liquid receiving hole. On the other hand, the interfaces of both liquids come into contact (liquid junction) near the center of the porous bridge, establishing electrical continuity. As a result, a potential difference corresponding to the difference in activity of each ion between the sample solution and the reference solution is generated between the electrodes of each ion-selective electrode pair, so if this potential difference is measured, the measured value and the previously determined Using a calibration curve (based on the Nernst equation), the ionic activities of Na, K, and Cl in the sample solution can be measured simultaneously, sequentially, or at any time.

As mentioned above, this type of ion activity measurement device can measure multiple ion activities by simply applying a small amount of the sample solution and reference solution once, so it is useful for the analysis of aqueous liquid samples, especially blood, etc. It is extremely useful in clinical analysis of samples taken from the human body.

However, in conventional ion activity measuring instruments, when a sample solution or reference solution is applied, it takes a certain amount of time for the sample solution or reference solution to penetrate into the porous liquid distribution member and reach the surface of each ion selection electrode. it takes time. Therefore, it took some time before potential difference measurement became possible. When the sample liquid is whole blood, hemolysis often occurs due to the large amount (surface area) of the porous liquid distribution member in contact with the whole blood, especially K ⁺
This caused problems in the measurement of ions.

Furthermore, in conventional ion activity measurement instruments, when a sample solution or reference solution is applied, bubbles are generated when the solution contacts the porous liquid distribution member, and these bubbles migrate to the electrode surface and become trapped. This sometimes caused errors in the measurement of electrode potential.

(Objective of the Invention) The object of the present invention is to shorten the time required for the sample solution and reference solution to reach the electrode surface, thereby shortening the time required for ionic activity measurement, and preventing the influence of hemolysis of the whole blood sample solution. It is an object of the present invention to provide an ion activity measuring instrument that does not cause any trouble in measurement due to the generation of bubbles.

(Structure of the Invention) The above object of the present invention has been achieved by employing a structure in which the liquid to be measured (sample liquid and reference liquid) is supplied from the end side surface of a sheet-like porous liquid distribution member.

That is, the above-mentioned object of the present invention is to provide at least one pair of sheet-like ion-selective electrodes that are electrically separated from each other and have an ion-selective layer on the surface, a reference liquid and a reference liquid on the surface of the ion-selective layer of each ion-selective electrode. An ion activity measurement instrument having a porous liquid distribution member for supplying sample liquids respectively, and a bridge for electrically conducting a reference liquid and a sample liquid to each other, the porous liquid distribution member connecting the liquid distribution member to each other. It is characterized in that it covers only a part of the bottom of the housing frame body, and its end part is provided so as to protrude into a part of the area below the liquid supply hole provided in the frame body. This was achieved using an ion activity measurement device. Note that in this specification, the expressions "protrude" and "face" include the case where the liquid supply hole and the liquid distribution member are in contact with each other only at a portion of the side surface. "Frame"
generally refers to a frame provided for holding at least an ion-selective electrode and/or a bridge. "Liquid supply hole" means an opening made through such a frame for injecting a sample solution or reference solution from outside the ion activity measuring instrument using a liquid measuring container such as a pipette. do.

The shape of the end of the porous liquid member (in the projected plane as seen from the direction perpendicular to the direction in which liquid distribution advances) is not particularly limited, but it may be a straight line, an arc (convex or concave), or any other curved line. . Alternatively, the shape may be a part of a polygon (for example, a hexagon or an octagon).

It is also possible to arrange more than one distribution member facing the liquid supply hole.

Line bandage cloth, cotton gauze, PET gauze, knitted fabric (e.g.
Porous liquids made of woven or knitted fabrics with relatively small weaves or stitches, such as cotton tricots, or nonwoven fabrics with small continuous voids made of cotton fibers, regenerated cellulose fibers, or synthetic polymer fibers (e.g. Bemliese) or paper, etc. In the distribution member, when a sample liquid having a relatively high viscosity is applied from a direction perpendicular to the longitudinal direction of the fiber, it takes a relatively long time for the sample liquid to permeate the fiber. Therefore, it is important that these porous members having small textures, stitches, or continuous voids have the structure according to the present invention (that is, the liquid is mainly supplied from the cut ends of the fibers).

The porous liquid distribution member is positioned such that its end portion protrudes into the liquid supply hole. The liquid supply hole may have any shape such as circular, oval, or polygonal, and its size is a circle with a diameter of about 1.5 mm to about 8 mm, or an oval or polygon inscribed in the circle. If there is a plurality of liquid distribution members, the spacing between them in the direction in which the liquid is distributed is about 1 mm to about 6 mm, preferably about 2 mm to about 3 mm.

(Embodiments) Hereinafter, preferred embodiments of the present invention and their main effects will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is an exploded perspective view of a multi-item ion activity measuring instrument which is an embodiment of the present invention, and FIG. 2 is a perspective view of the device after assembly. The ion activity measurement device shown in these drawings includes a lower support frame 100; three types of ion-selective electrode pairs 201 (same ion-selective electrodes 211);
and 221), 202 (consisting of 212 and 222), 203 (consisting of 213 and 2
23); liquid receiving holes 311, 312, 313, 321, 322 penetrating each of the ion electrodes;
Water-impermeable member layer 300 with adhesive layers on both sides provided with 323; liquid receiving holes 311, 312, 313
(That is, the ion selection electrodes 211, 212,
213) and the liquid receiving hole 321,
322, 323 (i.e., the liquid receiving holes penetrating the ion-selective electrodes 221, 222, 223), respectively.
10A, 410B and 420A, 420B; an upper frame 500; and a porous bridge (preferred specific example: a twisted thread bridge made of polyethylene terephthalate fiber) 600. The porous liquid distribution members 410A and 410B face the liquid spotting hole 510,
Porous liquid distribution members 420A, 420B are provided in a symmetrical relationship to liquid spotting holes 520. The upper frame 500 has porous liquid distribution members 410A and 41.
Liquid spotting holes 510 and 520 penetrating through 0B and 420A, 420B, respectively; air vent hole 5 for promoting liquid distribution in the liquid distribution member
31, 532, 541, 542 and ion selection electrodes 211, 212, 213, 221, 222,
Measurement probe insertion holes 561, 562, 563, 571, 572, 57 penetrating through 223, respectively
3 is provided. Liquid spot holes 510 and 52
Porous bridge 600 is placed at the opposite position sandwiching 0.
is fixed at both ends.

In such an ion activity measuring instrument, for example, the ion selective electrodes 201, 202, and 203 are used as ion selective electrode pairs for Na, K, and Cl, respectively, and a reference liquid whose ion activities are known is placed in a liquid spotting hole. 510 and a sample liquid whose ion activity is unknown is applied to the liquid spotting hole 520, the reference liquid permeates into the porous liquid distribution members 410A, 410B and flows through the liquid receiving holes 311, 410B. At 312 and 313, the sample liquid permeates into the porous liquid distribution members 420A and 420B and is distributed to the liquid receiving holes 321, 322, and 323. As mentioned above, in the ion activity measurement device shown in this embodiment, the porous liquid distribution members 410A and 410B are separated by the gap 430, and the porous liquid distribution members 420A and 420B are separated by the gap 440. Therefore, the sample liquid or reference liquid flows through these gaps into the porous liquid distribution members 410A, 410.
B, 420A, and 420B are supplied to the end sides. In this way, the liquid receiving holes 311, 312, 31
As a result, the reference liquid is distributed to the ion selective electrode 211 and the sample liquid is distributed to the liquid receiving holes 321, 322, and 323.
and 221, between 212 and 222,
Since potential differences corresponding to the differences in the ion activities of Na, K, and Cl between the reference solution and the sample solution occur between the reference solution and the sample solution, respectively, between the measurement probe insertion ports 561, 562, 563, and 571. ，
572 and 573, and make contact with each electrode, and measure the potential difference, the ion activity in the sample liquid can be measured in the same way as a conventional multi-type (multi-item measurement type) ion activity measuring instrument. can be measured.

FIG. 3 is a plan view showing the porous sample liquid distribution member according to this embodiment.

The porous liquid distribution member shown in FIG.
20A and 420B, with a gap of 440
are arranged so that a is formed between them. Since this gap 440 is narrower than the width of the liquid spotting hole 520, one end side surface of the liquid distribution members 420A and 420B protrudes into a part of the area below the spotting hole 520.

Further embodiments will be described in detail with reference to the ion activity measuring instrument shown in the accompanying drawings.

FIG. 4 is a perspective view showing an example of the ion activity measuring instrument of the present invention. FIG. 4A is an elevational sectional view taken along the line A-A of the ion activity measuring device shown in FIG. 4, FIG. 4B is a bottom view of the ion activity measuring device shown in FIG. FIG. 4C is an enlarged view of the encircled portion X of the elevational sectional view shown in FIG. 4A.

FIG. 5 is a diagram showing each component separately in order to explain in detail each component constituting the ion activity measuring instrument shown in FIG. 4.

The ion activity measuring device of the embodiment shown in these figures includes three pairs of sheet-like ion selective electrodes (one pair of ion selective electrodes has an ion selective layer on the top).
11a, 11b, and 11c (consisting of a combination of an ion-selective electrode for a reference solution and an ion-selective electrode for a sample solution that are electrically separated from each other) are arranged so that the ion-selective layer is on the lower side. The sheet-like ion-selective electrode has a support 11 made of, for example, a plastic sheet, as shown in FIG. 4C.
1, a metal silver vapor deposition layer 112, a silver chloride layer 113,
The electrolyte layer 114 and the ion selection layer 115 are laminated, and the sheet-like ion selection electrode thus constructed is placed in a measurement instrument with the support facing upward.

As shown in FIG. 4A, a liquid applying section for applying a reference liquid and a sample liquid to the surface of the ion selective layer of the ion selective electrode has an upper liquid supply hole 13, which supplies the liquid to the surface of the ion selective layer. It is composed of a horizontal passage 14 for horizontally moving the liquid directly below the liquid, and rising passages 15a, 15b, and 15c for raising the liquid to the surface position of each ion-selective layer. The horizontal passage 14 accommodates a liquid transfer member 16 having continuous fine gaps (referred to herein as porous) that can cause capillary action.
Note that the liquid transfer member is connected to the rising passages 15a, 15.
b, 15c may also be accommodated.

An air vent hole 17 is provided at the tip of the horizontal passage 14 to facilitate the transfer of liquid.

Three pairs of ion selection electrodes 11a, 11b, 11c
is housed and fixed in an upper frame 18 made of plastic. This upper frame 18 is provided with two openings 12 for applying liquid, and these two openings for applying liquid (a reference liquid applying opening and a sample liquid applying opening) A bridge (for example, a yarn bridge such as polyethylene terephthalate fiber twisted yarn (spun yarn)) 19 for electrically conducting the liquids (reference liquid and sample liquid) applied to the respective openings so as to cross the is provided.

Although not shown in the figure, the liquid application opening 12
A small protrusion area is provided around the opening to prevent the liquid to be dripped from overflowing to the outside of the opening, and to easily and reliably guide the liquid to be dripped.

A sheet-like water-impermeable intermediate member (plastic mask) 20 is provided at the bottom of the upper frame 18. A part of the descending passage 13 for the liquid that is spot-supplied, and the ascending passages 15a, 15b, and 15 for the liquid.
c is formed as an opening in this sheet-like water-impermeable intermediate member 20. Water-impermeable intermediate member 2
0 is bonded to the lower surface of the upper frame body 18 using a heat-sensitive adhesive.

On the lower side of the sheet-like water-impermeable intermediate member 20,
A lower frame 21 made of plastic is provided.

The horizontal passage 14 is formed in the lower frame 21 as a recess. A porous liquid distribution member 16 is housed in this horizontal passage 14 and is fixed such that its end faces the liquid supply hole 13 but covers only a portion of its bottom.

Ion selection electrodes 1 are provided on both sides of the lower frame 12.
Each electrical connection area 2 of 1a, 11b, 11c
A notch 23 is provided to expose 2a, 22b, and 22c downward (see FIG. 4B).

The lower frame 21 is bonded to the lower surface of the water-impermeable intermediate member 20 with a heat-sensitive adhesive.

FIG. 6 shows another embodiment of the ion activity measuring device of the present invention, with each constituent member separated to explain in detail each component constituting the ion activity measuring device, similar to FIG. 5 above. FIG.

Also in the ion activity measuring instrument of the embodiment shown in this figure, three pairs of sheet-like ion selective electrodes 31a, 31b, 31c are provided with an ion selective layer on the top.
is arranged so that the ion selective layer faces downward.

Three pairs of ion selection electrodes 31a, 31b, 31c
is housed in a plastic upper frame 38,
Fixed. This upper frame body 38 is provided with a liquid supply hole 32 .

In FIG. 6, three pairs of ion selection electrodes are distributed into one pair and two pairs on the left and right sides of the liquid supply hole 33. By adopting such a configuration, the distance between the liquid supply hole 33 and the farthest ion selection electrode becomes shorter than in the example measuring instruments shown in FIGS. This is advantageous when using a liquid with high viscosity as a sample, such as liquids with high viscosity.

The upper frame 38 is provided with a bridge 39 that crosses the two liquid supply holes 51 and allows the liquids (reference liquid and sample liquid) applied to each of the liquid supply holes to be electrically connected to each other. ing.

A sheet-like water-impermeable intermediate member (for example, a plastic mask) 40 is provided below the ion-selective electrodes 31a, 31b, 31c. Part of the liquid supply passage 33 and the liquid rising passage 35
a, 35b, and 35c are formed as openings in this sheet-like water-impermeable intermediate member 40. The water-impermeable intermediate member 40 includes a bridge support member 52
and is bonded to the lower surface of the upper frame 38 with an adhesive (pressure-sensitive adhesive, heat-sensitive adhesive, etc.).

On the lower side of the sheet-like water-impermeable intermediate member 40,
A lower frame 41 made of plastic is provided.

The horizontal passage 34 is formed in the lower frame 41 as a recess. And this horizontal passage 34
Therein, a porous liquid distribution member 3 consisting of four parts.
6 is filled. This liquid distribution porous member 36
are fixed so that the ends of each portion face the liquid supply hole 33, but so as to cover only a portion of the bottom of the supply hole 33.

Ion selection electrodes 3 are provided on both sides of the lower frame 41.
A notch 43 is provided to expose the electrical connection area of each of 1a, 31b, and 31c downward (see FIG. 4B).

Furthermore, in the measuring instrument shown in FIG. 6, since the three ion-selective electrode pairs are distributed on both sides of the liquid descending passage 33, air vent holes 37a and 37b are provided at both ends of the lower frame 41. It is being

The lower frame 41 is bonded to the lower surface of the water-impermeable intermediate member 40 using a heat-sensitive adhesive.

In the ion activity measurement device of the present invention, it is not necessarily necessary to provide a gap between the two sets of porous liquid distribution members, and especially when the viscosity of the reference liquid is low, the porosity for distributing the sample liquid is not necessarily required. It is sufficient to provide a gap only in the liquid distribution member, and the reference liquid side is
-211648 can be used.

(Effects of the Invention) As described above in detail, the ion activity measurement device of the present invention has at least one of the porous liquid distribution members protruding into the liquid supply hole, thereby preventing hemolysis of whole blood sample liquid and This is an ion activity measuring instrument particularly suitable for measuring whole blood.

[Brief explanation of the drawing]

FIG. 1 is a perspective exploded view showing an ion activity measuring device according to an embodiment of the present invention, FIG. 2 is a perspective view showing the device after assembly, and FIG. 3 is a porous liquid distribution device according to an embodiment of the present invention. FIG. 4 is a plan view showing the members, and FIG. 4 is a perspective view showing an example of the ion activity measuring instrument of the present invention.
Figure A is the ion activity measuring instrument shown in Figure 4.
- Fig. 4B is a bottom view of the ion activity measuring instrument shown in Fig. 4, and Fig. 4C is an elevational sectional view taken along line A; 5 is an enlarged view of the ivy portion , another aspect of the ion activity measuring instrument of the present invention,
Similar to FIG. 5 above, this is a diagram showing each constituent member separated so as to explain each member constituting the ion activity measuring instrument in detail. 11a, 11b, 11c... ion selective electrodes,
31a, 31b, 31c...Ion selective electrode, 1
11... Plastic sheet support, 112...
...Metallic silver vapor deposited layer, 113...Silver chloride layer, 114...
... Electrolyte layer, 115 ... Ion selective layer, 12,3
2...Liquid application opening, 13, 33...Liquid descending passage (liquid supply hole), 14, 34...Liquid horizontal passage, 15a, 15b, 15c...Liquid rising passage, 35a, 35b, 35c ...Liquid rising passage, 16, 36...Porous member for liquid transfer, 1
7, 37a, 37b... Air vent hole, 18, 38
... Upper frame body, 19, 39 ... Bridge, 20,
40... Water-impermeable intermediate member (mask), 21,
41... lower frame body, 22a, 22b, 22c...
Electrical connection area of ion selective electrode, 23, 43...
...Notch portion, 100...Lower support frame, 201, 2
02,203...Ion selective electrode pair, 211,2
12,213...One ion selection electrode, 22
1,222,223...the other ion selection electrode,
300... water impermeable member layer, 311, 312,
313... One liquid receiving hole, 321, 322, 32
3...Other liquid receiving hole, 410A, 410B, 42
0A, 420B...Porous liquid distribution member, 430,
440... Gap between liquid distribution members, 500... Upper frame, 510... One liquid spotting hole (liquid supply hole), 5
20...Other liquid spotting hole (liquid supply hole), 531,
532... One air vent hole, 541, 542...
...Another air vent hole, 551,552...Porous bridge fixing part, 561,562,563...One measurement probe insertion hole, 571,572,5
73...Other measurement probe insertion hole, 600...
...Porous bridge (twisted bridge).

Claims (1)

[Claims] 1. At least one pair of sheet-like ion selective electrodes electrically separated from each other having ion selective layers on their surfaces, and supplying a reference liquid and a sample liquid to the ion selective layers of each of the ion selective electrodes. at least one pair of porous liquid distribution members for supplying the reference liquid and the sample liquid to the liquid distribution members, respectively, and a pair of liquid supply holes disposed above each of the liquid distribution members for separately supplying the reference liquid and the sample liquid to the liquid distribution members. , a frame housing the ion selective electrode or porous liquid distribution member therein;
At least one liquid distribution member of the liquid distribution members in the ion activity measuring instrument comprising a porous bridge that electrically conducts the reference liquid and sample liquid that are spotted in the pair of liquid supply holes. covers only a part of the bottom of the frame housing the liquid distribution member, and its end protrudes into a part of the area below the liquid supply hole, allowing liquid to enter from the side surface of the end. An ion activity measuring instrument characterized by: 2. Among the liquid distribution members, at least an end of the porous liquid distribution member for supplying the sample liquid protrudes into a part of the region below the liquid supply hole, so that the liquid can enter from the side surface of the end. An ion activity measuring instrument according to claim 1, characterized in that: