JPH02134567A - Test piece for measuring chloride - Google Patents

Abstract

PURPOSE:To simply and rapidly measure the concn. of salt in a solution at any place at any time by anyone with accuracy sufficient from a practical aspect by supporting a water-soluble silver salt, a silver chelating reagent and a pH buffer by an absorbable carrier to use them in a test. CONSTITUTION:Filter paper is successively immersed in the first and second solutions to be dried. The first solution is prepared from 3.0g of 2-(N- morpholino) ethanesulfonic acid, 9.0g of sodium 2-(N-morpholino) ethanesulfonate, 1.0g of gum arabic, 3.2g of silver nitrate and 100ml or pure water, and the second solution is prepared from 0.05g of 2-(2-thiazolylazo)-p-cresol and 100ml of methanol. The obtained purple test paper is cut into a length of 10mm and the cut piece is adhered to one end of a plastic sheet of 10 X 85mm to obtain test paper. This test piece is immersed in an aqueous sodium chloride solution and, after about 30sec, the developed color state of the surface of the test paper is observed. A 0.5% aqueous sodium chloride solution becomes purple as a whole and a 1.0% aqueous sodium chloride solution becomes purple by about 50% and yellow by about 50%.

Description

[Detailed Description of the Invention] (Field of Industrial Application) In recent years, restriction of salt intake has become important as a prevention or dietary therapy for hypertension, and the Ministry of Health and Welfare in Japan recommends that the daily salt intake be 10 g or less, and in the United States it is 5 g. We recommend that you do the following:

However, this recommendation is not always followed, and it is said that even about half of hypertensive patients consume 10 g or more of salt per day.

The reason for this is that each individual does not have a numerical guideline for their daily salt intake, and even if they think they are on a salt-reduction regimen, they actually ingest more than 10g/day of salt. Ta. Therefore, there is a need for a simple method for determining the extent to which salt reduction has progressed or for estimating daily salt intake.

Currently, the most accurate method for measuring daily salt intake is to measure the daily sodium concentration in urine and convert it into the amount of salt excreted.

Flame photometers, ion meters, etc. are used to measure urinary sodium concentration.

Recently, it has been found that the sodium concentration in urine has a very good correlation with the chloride concentration, and both are excreted almost equally. Another method is to measure the amount of salt and convert it into the amount of salt excreted.

The method for measuring urinary crawl is 5chales-Sch.
Ales method (titration with mercuric nitrate using diphenylcarbazone as an indicator), Fajans method (using fluorescein as an adsorption indicator during chloride titration with silver nitrate), etc. are commonly used.

However, the above-mentioned titration method requires relatively complicated measurement operations, and cannot be carried out by anyone, anytime, and anywhere.

Recently, salt tapes using the Fajans method have been released (Japanese Patent Application Laid-open Nos. 177266-1982 and 1021-1983).
No. 58, Japanese Unexamined Patent Publication No. 62-102159). Although the measurement operation has been simplified, it seems that accuracy and stability are still insufficient.

(Problems to be solved by the invention) As described above, the conventional method is l) complicated to operate, 2) requires experience for measurement, 3) measuring equipment is expensive, 4) measurement location is limited, and 5) harmful. It has various disadvantages such as the use of metal and 6) poor stability of the reagent.

(Means for Solving the Problems) The present invention was made in view of the above circumstances, and its purpose is to provide a stable reagent that is sufficient for practical use without using harmful metals such as mercury compounds. To provide a method and means for accurately, simply, and quickly measuring the salt concentration in a liquid by anyone, anytime, and anywhere.

That is, the gist of the present invention resides in a test piece for measuring chloride in a liquid, characterized in that a water-soluble root salt, a silver chelate reagent, and a PT+ buffer are supported on an absorbent carrier.

The principle of the present invention is to form a silver complex from a water-soluble root salt and a silver chelating reagent.

Silver complex and chloride ion react to produce silver chloride.

Reaction formula 2-(2-thiazolyl azo)-p as a silver chelating reagent
- When using cresol 2 (C+oLNiQS) + Ag'-Ag(C+oLNiQS)
)IJ30SL Yellow Purple Ag (C+ oHJ*Os) z +CIl--AgC
1+ 2 (C+ oHJ30s) Purple
Yellow. When 2-(2-thiazolyl azo)-p-cresol is in excess, the composition ratio with silver is 1:2.

2-(2-thiazolyl azo)-p-cresono L7Ag
The structure of the complex appears to be as follows.

The water-soluble root salt used in the present invention is silver nitrate.

Examples include silver malonate and silver lactate. Among these, it is advantageous to use silver nitrate, which is the most stable and has excellent solubility.

As a silver chelating reagent, thiazolyl azo-based chelating reagents are good, specifically 2-(2-thiazolyl azo).
-p-cresol, 4-(2-thiazolyl azo)-resorcinol, and 2-(2-thiazolyl azo)-5-dimethylaminophenol. Among these, 2-
Preference is given to using (2-thiazolyl azo)-P-cresol.

In the manufacture of test strips it is used in concentrations of 0.01-0.5% by weight, preferably 0.05-0.2% by weight.

As the pH buffer, any known buffer that can maintain pH 3 to 7 can be used.

If high buffering properties are required depending on the type of test solution, it is desirable to use a buffer that does not react with silver salts (silver nitrate, etc.) to form a precipitate. Acid acid derivatives are used.

A preferred buffering agent is 2-(N-morpholino)
Ethanesulfonic acid (MES) Bis(2-hydroxyethyl)iminotris(hydroxymethyl)meta-7 (BI 5-TRIS) Piperazine-N,N'-bis(2-ethanesulfonic acid) (PI
FES) 3-(N-morpholino)propanesulfone M (Mops
) etc. These pH buffers are used in the production of test strips at 0.05M/I! , preferably 0.1 to 0.5
M/I! , used in concentrations.

The test strip of the present invention is manufactured by the following method. That is, a filter paper is immersed in a mixed solution of water-soluble silver and a pH buffer, then pulled up and dried, then dipped in an organic solvent of a silver chelate reagent, pulled up and dried. Alternatively, water-soluble silver, a chelating reagent, and a pH buffer may be dissolved in water or an organic solvent that is miscible with water, and a filter paper may be immersed in this solution and then pulled out and dried.

The thus dried test paper is pasted on a plastic sheet or the like and cut into a suitable size and shape to obtain a test piece.

To measure the chloride concentration in a liquid using this test piece, the test piece is brought into contact with the test liquid, and after a certain period of time, the chloride concentration is measured by comparing it with a standard color chart prepared in advance.

It is clear that it is possible to measure the chloride concentration in liquids other than body fluids, such as seawater, lubricating oil, miso soup, and ready-mixed concrete, and it is obvious to those skilled in the art that various modifications can be easily made.

EXAMPLES Hereinafter, the present invention will be explained in more detail in Examples, but the scope of the present invention is not limited thereby.

Example 1 Filter paper (Toyo Roshi No. 3) was soaked in the following solutions in order and dried.

First solution 2-(N-morpholino)ethanesulfonic acid 3.0g2-(N
-morpholino) Sodium ethanesulfonate 9.0g Gum arabic 1.0g Silver nitrate
3.2g pure water 100mf 2nd? Solution 2-(2-thiazolyl azo) -p Cresol 0.05 Methanol 100 mjl! The obtained purple test paper was cut into 10 m/m squares and pasted on one end of a 110 x 85/m plastic sheet to prepare a test paper of the present invention.

This test piece is immersed in an aqueous sodium chloride solution, and after about 30 seconds, the state of color development on the surface of the test paper is observed.

1) Sodium chloride 0.5% aqueous solution The whole is purple 2) IJum 0.8% aqueous solution About 75% is purple, about 25% yellow 3) Sodium chloride 1.0% aqueous solution About 50% is purple,
Approximately 50% yellow 4) Sodium chloride 1.2% aqueous solution Approximately 25% purple,
Approximately 75% yellow 5) Sodium chloride 1.6% aqueous solution The whole is yellow As mentioned above, as the sodium chloride concentration increases, the proportion of yellow coloring in the test piece increases. In addition, the test piece of Example 1 above was placed in a sealed container (brown bottle containing desiccant) and heated at 40''C.
stored in an atmosphere of

When the product was taken out after two months and the state of discoloration was observed, it was found to be almost the same as immediately after production, and the stability was good.

Example 2 The amount of silver nitrate in Example 1 was 1.2 g and 1.6 g.

2.2 g, 2.5 g, 3.0 g, 3.
Six types of test strips were prepared using exactly the same formulation except that the amount was changed to 2 g.

In descending order of silver nitrate concentration: a, b, c, d,
Let them be e and f. Each test paper (a-f) at 5 m/m
A test piece is prepared by cutting into corners and pasting them in the order of a, b, c, d, e, and f from the tip of a plastic sheet measuring 5+++/m x 85 m/m. Each test paper is 0.
6,0.8°1.0. 1.2. 1.4. 1.6%
The entire test paper turns yellow in an aqueous solution of sodium chloride.

Therefore, it is possible to measure the sodium chloride concentration in the liquid from the degree of discoloration of each test paper. Furthermore, when the specimen was stored in an airtight container (a brown bottle containing a desiccant) at 40°C, it showed good stability similar to the test piece of Example 1.

Next, in order to objectively demonstrate the performance of the test piece for measuring chloride of the present invention, the urinary sodium chloride concentration of normal sweat was determined using the test piece prepared based on Example 2 using an ion meter (Hitachi Horiba Manufacturing Co., Ltd.). Comparison was made with the sodium chloride concentration calculated from the sodium concentration measured with N-8M).

The results are shown in FIG.

(Effects of the Invention) As mentioned above, the test piece for chloride measurement of the present invention shows a high correlation with an ion meter (r=0.968), and does not use harmful total bending like mercuric nitrate. Since no expensive measuring machines or special instruments are required, measurements can be performed at low cost, and no technical skill is required for measurement, so any person can easily and quickly perform measurements.

Furthermore, the test piece of the present invention has good stability, can be easily carried, can be used both indoors and outdoors, and is extremely effective in measuring chloride concentrations in liquids.

[Brief explanation of the drawing]

Figure 1 shows the urinary sodium chloride concentration of a healthy person using a test piece prepared according to Example 2, and a comparison with the sodium chloride concentration calculated from the sodium concentration measured with an ion meter (Hitachi Horiba N-8M). This is a chart showing the results.

Claims (2)

[Claims] (1) A test piece for measuring chloride, characterized in that a water-soluble silver salt, a silver chelating reagent, and a pH buffering agent are supported on an absorbent carrier. (2) The silver chelating reagent is 2-(2-thiazolyl azo)-
The chloride according to claim 1, which is selected from the group consisting of p-cresol, 4-(2-thiazolyl azo)-resorcinol, and 2-(2-thiazolyl azo)-5-dimethylaminophenol. Test piece for measurement.