JPS60260843A - Measuring instrument for ionic activity - Google Patents

Abstract

PURPOSE:To make the handling of an instrument easier than the conventional fixing method using an adhesive agent as well as to eliminate the incorporation of the adhesive agent into liquid and to enable measurement with high accuracy by fixing a porous bridge connecting reference liquid and sample liquid by a liquid-junction by means of detaining plugs to supporting frames. CONSTITUTION:The measuring instrument for ionic activity consists of the lower supporting frame 10, an ion selecting electrode pair 20 which consists of the same specific ion selecting electrodes 21, 22 and are electrically insulated by a scratched groove or machined groove, a water impermeable member layer 30 which is provided with through-holes 31, 32 and have adhesive agent layers on both sides, the upper supporting frame 40 provided with spotting holes 41, 42 and detaining holes 43, 44, the porous bridge 50 and the detaining plugs 63, 64. The plugs 43, 44 are provided in the position where the plugs face each other on the outside with the holes 41, 42 in-between. Both ends of the bridge 50 are fixed by the plugs 63, 64. The measurement of the ionic activity is executed by spotting the reference liquid to the hole 41 and the sample liquid to the hole 42, measuring the potential difference between the electrodes 21 and 22 and calculating the ionic activity in the sample from the preliminarily determined calibration curve.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to the activity of specific ions in aqueous liquid samples, such as alcoholic beverages, drinks, tap water, and especially biological fluids (blood, urine, saliva, etc.). This invention relates to an ion activity measurement device for quantitatively analyzing (or concentration) by potentiometry.

(Prior art) Slide-type ion activity measuring instruments capable of spotting a liquid sample and measuring the activity of specific Φ ions contained therein are disclosed in JP-A-58-211648 and JP-A-59. -3
It is disclosed in No. 0055 and the like.

Generally, these ion active JHI devices are provided with at least one pair of ion-selective electrodes having an ion-selective layer as the outermost layer that selectively responds to specific ions, and the pair of ion-selective electrodes is connected to two upper and lower supports. A pair of spotting holes each consisting of one hole penetrating each electrode of the pair of ion-selective electrodes is mounted on the upper support frame, and a sample liquid is spotted and supplied to one of the pair of spotting holes, and the other of the pair of spotting holes is sandwiched between the frames. A porous bridge (twisted string made of string) is provided to achieve electrical continuity (liquid junction) with the reference liquid that is dot-supplied.

This type of ion activity measuring device has excellent operability,
This was a breakthrough in ion activity measurement. However, until now, the porous bridge has been adhered to the upper support frame via a double-sided adhesive tape, etc., so the adhesive such as the double-sided adhesive tape seeps into the porous bridge, impeding the diffusion of the sample solution or reference solution. If it takes a long time to form a liquid junction or becomes impossible to measure, or if the adhesive strength weakens significantly, the porous bridge may separate from the upper support frame during handling.

(Objective of the Invention) In view of the problems of the prior art described above, an object of the present invention is to provide an ion activity measuring instrument that is capable of measuring ion activity with high precision and has a structure that is easy to handle.

(Structure of the Invention) The ion activity measuring instrument of the present invention is provided with at least one set of square holes at positions facing outwardly across the pair of spotting holes in the upper support frame, and at both ends of the porous bridge. are arranged in respective square holes, and the porous bridge is fixed on the upper support frame by fitting a stopper that fits into each square hole.

In the present invention, the dimensions and shapes of the square holes and stopper plugs are not particularly limited, but it is preferable from the viewpoint of ion activity measurement that the porous bridge does not come into contact with the adhesive for fixing the ion-selective electrode.

The stopper may be made of any material as long as it is virtually inert to the sample solution and the reference solution and can fit into the square hole to fix the porous bridge. For example, It is also possible to use the fragments of the upper support frame obtained when punching and molding the square holes as they are, and in this case, manufacturing loss can be reduced.

(Actual/7I! Embodiment) Preferred embodiments of the present invention and their main effects will be described below based on the drawings.

FIG. 1 is an exploded perspective view of an ion activity measuring instrument according to an embodiment of the present invention, and FIG. 2 is a perspective view of the instrument after assembly.

The ion activity measuring instrument shown in these drawings is the lower support frame 1.
0, an ion-selective electrode pair 20 consisting of the same specific ion-selective electrodes 21 and 22 electrically insulated by a scratch groove or a cut groove, a water-impermeable member having adhesive layers on both sides provided with through holes 31 and 32 ( layer 30, which also serves to prevent electrical short circuits due to liquid leakage from around the spotting holes;
Upper support frame 40 provided with dot holes 41 and 42 and square holes 43 and 4/l, porous bridge (preferred specific example:
Polyethylene terephthalate fiber twisted yarn bridge) 5
0, and stopcocks 63 and 64. The square holes 43 and 44 are provided at opposing positions on the outside with the spotting holes 41 and 42 in between, and fix both ends of the porous bridge 50 together with the fitting □ stoppers 63 and 64, respectively. Note that if the square holes 43 and 44 are provided at positions offset from the straight line connecting the center points of the spotting holes 41 and 42 and the porous bridge is located near the periphery of both point pipe holes, the porosity will be removed when liquid is spotted and supplied. The liquid from the bridge is less likely to cause wrinkles,
In addition, there is no risk of damaging the porous bridge at the tip of a liquid spot supplying device such as a micropipette when liquid is dispensed, which is preferable.

FIG. 3 is a perspective view showing a partially modified example of the ion activity measuring instrument shown in FIGS. 1 and 2. FIG. In the embodiment shown in this drawing, a recessed area 45 is provided between the spotting hole 41 and the spotting hole 42.
A porous bridge 50 and an upper support frame 4 are provided.
This prevents capillary action of the aqueous liquid in the gap between the water and the water. If capillarity occurs in this gap, there is a possibility that the sample liquid and reference liquid spotted in each of the spotting holes 41 and 42 will mix with each other. It is preferable to provide one.

Next, the operation of the ion activity measuring instrument shown in FIGS. 1, 2, and 3 will be explained.

When a reference liquid in which the activity (or concentration) of a specific ion is known is spotted in the spotting hole 41 and a sample liquid in which the activity of the ion is unknown is spotted in the spotting hole 42, the reference liquid becomes water. The sample liquid passes through the through hole 31 in the impermeable member 30 and reaches one ion selective electrode 21 of the ion selective electrode pair 20 that generates a potential corresponding to the activity of the ion. and reaches the other ion selection electrode 22. On the other hand, the interfaces of both liquids come into contact (liquid junction) near the center of the porous bridge 50, and electrical continuity is established. As a result, a potential difference corresponding to the difference in activity of the ions between the sample solution and the reference solution is generated between the ion selection electrodes 21 and 22, so if this potential difference is measured, the measured value and the ions of the reference solution are The ion activity in the sample solution can be excluded using a calibration curve (the principle is based on Nernst's equation) prepared in advance from the activity.

FIG. 4 is a perspective exploded view of an ion activity measuring instrument that can measure the activities of three different ions (multi-item measurement type), which is another IM embodiment of the present invention, and FIG. 5 is an exploded view of the ion activity measuring instrument after assembly. FIG. The ion activity measurement device shown in these drawings includes a lower support frame 100, three different ion selection electrode pairs 201 (consisting of the same ion selection electrodes 211 and 221), 202 (consisting of the same ion selection electrodes 212 and 222), and , 203 (consisting of 213 and 223), through holes 311.312.313.321.322 and 32
Water-impermeable member layer 30 having adhesive layers on both sides provided with 3
0, spotting hole 41L 412.413.42L 422 and 443 and square hole 431.432.433.441.44
2 and 443, porous bridges 501, 502 and 503, and stopper 631
．． 632.633.641.642 and 643.

In this embodiment, one pair of square holes is arranged in the same positional relationship as the embodiment shown in FIGS. 1 and 2 for each pair of spotting holes corresponding to each pair of ion-selective electrodes. has been done. These square holes secure the ends of each porous bridge with their respective mating stoppers as in the previous embodiments.

In the multi-item measurement type ion activity measuring device of this embodiment, for example, the ion selective electrode pairs 201, 202, and 203 are used as ion selective electrode pairs for NaΦ, K■, and C10, respectively, and the activities of these ions are known. A reference solution having the following properties is spotted in the spotting holes 411, 412 and 413, and a sample solution whose ion activity is unknown is spotted in the spotting holes 421, 422 and 42.
3, liquid junctions occur at the porous bridges 501, 502 and 503, respectively, and the ion selective electrode 2
Between 11 and 221, between 212 and 222, and between 213 and 223, there are potential differences corresponding to the differences in the ion activities of Na'', K■, and C10 between the reference solution and the sample solution, respectively. occurs.

Therefore, the ion activities of these three types in the sample solution can be measured simultaneously, sequentially, or at any time.

Although some embodiments of the present invention have been described above, it goes without saying that various modifications can be made thereto.

As an example of the modification, the water-impermeable members 30 and 300 prevent liquid from leaking (liquid around) from around the liquid spotting hole to the ion-selective electrode, and further protect the ion-selective electrode from the upper support frame and the lower support frame. Although it is provided for the purpose of fixing between the frames, it may be omitted. Further, on the electrode side of this water-impermeable member, a non-plasticized adhesive layer, such as a hot-melt adhesive layer disclosed in JP-A No. 59-30055, etc., is applied (however, in the through-hole of the water-impermeable member). If a corresponding through-hole is provided), the ion-selective electrode can be fixed more reliably, and liquid (reference liquid or sample liquid) can be prevented from leaking from around the through-hole.

This unplasticized adhesive layer may be integrated with the water-impermeable member layer. That is, an adhesive that is not plasticized may be provided on the electrode-side surface of the water-impermeable member layer instead of the tacky adhesive layer.

(Effects of the Invention) In the ion activity measurement device of the present invention, the porous bridge that connects the reference liquid and the sample liquid is fixed on the upper support frame without contacting the adhesive. There is no contamination with the reference or sample solution, a liquid junction is formed reliably in a very short time, and highly accurate ionic activity measurements are therefore possible. It is also easier to handle because it is fixed more securely than in the case of other cases.

[Brief explanation of drawings]

FIG. 1 is a perspective exploded view showing an ion activity measuring device which is an embodiment of the present invention, FIG. 2 is a perspective view showing the device after assembly, and FIG. 3 is a perspective view showing a partially modified example of the above embodiment. FIG. 4 is an exploded perspective view showing an ion activity measuring device according to another embodiment of the present invention, and FIG. 5 is a perspective view showing the device after assembly. 10.100... Lower support frame 20.201.202.203... Ion selection electrode pair 21.211.212.213... One ion selection electrode 22.221.222.223... Other Ion selective electrode 30.300...Water impermeable member layer 31.311.312.313...One through hole 32
．． 321.322.323...Other through hole 40.4
00 ... Upper support frame 41.411.412.413 ... One spotting hole 42
．． 421.422.423...Other spotting hole 43.4
31.432.433...One square hole 44.441.
442.443...Other square hole 45...Recessed area 50.501.502.503...Porous bridge (
Twisted thread bridge) 63.631.632.633...One stopper 64.
641.642.643...Other stopper Fig. 1 9-/63 Chest 2 Fig. 11 and 3 Fig. 4 Fig. 115 Fig.

Claims (1)

[Claims] (1) A lower support frame, at least one pair of ion-selective electrodes arranged on the support frame, and a spotting hole arranged on the pair of ion-selective electrodes and penetrating through each electrode of the pair of ion-selective electrodes. an upper support frame, a sample solution spotted in a spotting hole penetrating one electrode of each of the electrode pairs, and a reference solution spotted in a spotting hole penetrating the other electrode of each electrode pair; In the ion activity measuring instrument having a porous bridge that electrically conducts the electrodes, the lower support frame is provided with a pair of spotting holes corresponding to the pair of ion-selective electrodes at positions facing outwardly from each other between the pair of spotting holes. , at least one set of retention holes are provided, and both ends of the porous bridge are fixed to the upper support frame by the retention holes and closure plugs that fit the retention holes. utensils.