JPH0783912A - Method for preserving test paper containing acid or base indicator - Google Patents

Abstract

PURPOSE:To prevent the discoloration and exudation of a test paper containing acid or base indicator by using a drying agent with gas adsorption property or absorption property or using a gas adsorption agent or a gas absorption agent and the drying agent. CONSTITUTION:A drying agent with gas adsorption property or absorption property includes synthetic zeolite such as zeolum and molecular sieves, slaked lime, etc., and one type out of these or a substance containing these desiccants as constitution components is used. For the synthetic zeolite, it is desirable that an adsorption hole diameter is equal to or longer than 4Angstrom . The gas adsorption agent or gas absorption agent includes slaked lime, soda lime, etc., and a desiccant which is combined with it includes natural or synthetic zeolite, slaked lime, silica gel, calcium chloride etc. These substances are combined individually or in combination and are enclosed in a test paper and both water and carbon dioxide in air are eliminated, thus preventing the test paper from being discolored and squeezed out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preserving a test strip containing an acid-base indicator, and more particularly to a method for preserving a high-sensitivity test strip among test strips containing an acid-base indicator.

[0002]

2. Description of the Related Art A test paper containing an acid-base indicator may be discolored or the reagent may exude during storage.
Therefore, in order to prevent this, a method of enclosing a silica gel desiccant in a highly airtight container or storing it in a low temperature place such as a refrigerator is adopted. On the other hand, although highly sensitive test papers have been developed,
It deteriorated easily and was difficult to put into practical use as a test paper.

[0003]

The high-sensitivity test paper as used herein means that the measurement resolution is 1 or less in the case of pH test paper, and the acid value of 0 to 1 is accurate in the case of acid value measurement test paper. What can be measured well. In the test paper containing the above-mentioned highly sensitive acid-base indicator, the silica gel desiccant is enclosed together using a highly airtight container, or the method of storing it at a low temperature place such as a refrigerator prevents its discoloration, A sufficient effect cannot be obtained to prevent the reagent from seeping out. In particular,
When the container is used frequently, the container is often opened and closed, and therefore the discoloration and the exudation of the reagent are likely to proceed, which makes the container unusable.

The present invention has been made in view of the problem during storage which makes it difficult to put a test paper containing a highly sensitive acid-base indicator into practical use, and its purpose is to store the test paper during storage. It is a storage method that does not discolor or exude the reagent, especially when the test paper containing the acid-base indicator does not discolor or bleed out of the reagent, even if it is frequently used and the storage container is often opened. Is to provide a method.

[0005]

[Means and Actions for Solving the Problems] As a result of various studies to overcome the above problems, the present inventors have clarified the following regarding discoloration of test strips and exudation of reagents. did. That is, test papers containing acid-base indicators such as acid value measurement test papers for fats and oils, litmus test papers, pH test papers, etc., because moisture in the air adheres to the band (the surface coated with the indicator), Carbon dioxide in the air melts, the pH drops, and the indicator discolors. In particular,
When a basic compound, a wetting solvent, or a surfactant is used as the neutralizing agent, carbon dioxide or moisture is often absorbed, and discoloration or exudation of the reagent is often caused. Then, the discoloration of the reagent occurs only by removing the moisture by the conventional desiccant. Further, the removal of only carbon dioxide by the gas adsorbent or the gas absorbent can prevent discoloration of the reagent, but exudes the reagent due to water. Therefore, the inventors have found that by removing both water in the air and carbon dioxide, which are the causes of discoloration, from the system, it is possible to prevent discoloration of the reagent while preventing discoloration.

The present invention is based on the above findings, and its concrete means is to use a test paper containing an acid-base indicator as a desiccant having a gas adsorbing property or an absorbing property, particularly a carbon dioxide adsorbing or absorbing function. A method of storing a test strip containing an acid-base indicator consisting of enclosing it in a container together with a test strip containing an acid-base indicator in a container together with a gas adsorbent or gas absorbent and a desiccant. This is a method for storing a test strip containing an acid-base indicator.

Examples of test papers to be preserved according to the present invention include oil and fat acid value measurement test papers, litmus test papers, and pH test papers. Particularly, the acid value measuring test paper is a highly sensitive one capable of accurately measuring an acid value of 0 to 1, and the pH test paper is a highly sensitive one having a measurement resolution of 1 or less. The desiccant having gas adsorbability or absorbability used in the present invention is synthetic zeolite such as Zeolum or molecular sieves or quicklime, and one or more selected from these or these desiccants as constituent components. Inclusions can be used. The synthetic zeolite preferably has an adsorption pore size of 4 angstroms or more. Furthermore, in the present invention, a test paper containing the above-mentioned acid-base indicator is enclosed together in a container by using an ordinary desiccant in combination with a desiccant having a gas adsorbing property or an absorbing property. It is possible to exert an effect. Next, the gas adsorbent or gas absorbent used in claim 3 of the present invention is one or more selected from slaked lime and soda lime, and the desiccant is also a natural or synthetic zeolite, quicklime, silica gel, It is possible to use one or more selected from calcium chloride, magnesium chloride, calcium-silica-alumina clay or one containing these desiccants as a constituent.

As described above, the present invention is characterized in that a gas adsorbent or absorbent desiccant is used, or a gas adsorbent or a gas absorbent and a desiccant are used in combination. The effect cannot be obtained even if the gas absorbent alone or the desiccant which does not absorb or absorb gas is used alone. The desiccant, gas adsorbent or gas absorbent used in the present invention is preferably a commercially available product packaged in a gas permeable material and does not come into direct contact with the test paper. Further, the shape thereof may be granular, powdery, tablet, sheet-like one adsorbed on a porous material such as pulp or plastic, and may be solid one.

The present invention uses a desiccant having gas adsorbability or absorbability as described above, or uses a gas adsorbent or a gas adsorbent in combination with a desiccant, and encloses it in a container together with a test strip for storage. However, according to this method, both water and carbon dioxide in the air can be removed from the system, preventing discoloration of the test paper even when it is frequently used and the container is often opened and closed. It is possible to prevent the reagent from seeping out.

[0010]

EXAMPLES Examples will be described below. Example 1 10 pieces of simple oil and fat acid value measurement test paper and 2 g of molecular sieves 4A (manufactured by Wako Pure Chemical Industries, Ltd.) as a desiccant having gas adsorbability were wrapped in a polypropylene sheet having holes, and 150 ml thereof was wrapped. It was put in a glass bottle and put on a screw cap with silicone packing. This was stored at room temperature, and the cap was opened once a day and the outside air was introduced to observe the discoloration of the indicator and the exudation of the reagent. As a result, the discoloration of the indicator and the exudation of the reagent were not seen even after two months. The above-mentioned simple oil and fat acid value measurement test paper used in this example is composed of an acid-base indicator having a color change range in the range of pH 6 to 10, a basic substance, and a non-volatile wettable organic solvent. The value has a measuring function in the range of 0 to 4. In addition,
Table 1 shows the results of this example and the following examples and comparative examples.

Example 2 When 2 g of quicklime was used as a desiccant and the same procedure as in Example 1 was performed, discoloration of the indicator and exudation of the reagent were not observed even after 2 months.

Example 3 Ten pieces of simple oil and fat acid value measuring test paper, slaked lime-based gas absorbent (Ageless C-250P, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 2 g of silica gel as a desiccant were put into a 150 ml glass bottle at the same time, A screw cap with silicone packing was used. This was stored at room temperature, and the cap was opened once a day and the outside air was introduced to observe the discoloration of the indicator and the exudation of the reagent. As a result, neither discoloration of the indicator nor exudation of the reagent was observed even after two months had passed.

Comparative Example 1 10 sheets of simple oil and fat acid value measuring test paper and 1 g, 2 g and 5 of silica gel packed as a desiccant.
g was placed in a glass bottle, and a screw cap with silicone packing was put on. Store this at room temperature, 1 a day
The stopper was opened at a rate of once and the outside air was put in, and the discoloration of the indicator and the exudation of the reagent were observed. As a result, the indicator changed its color in 2 to 5 days.

Comparative Example 2 Ten simple oil / fat / acid number measuring test papers and a slaked lime gas absorbent (Ageless C-250P, manufactured by Mitsubishi Gas Chemical Co., Inc.) were put in a glass bottle and a screw cap with a silicone packing was put on the glass bottle. Store it at room temperature and
The cap was opened once a day and the outside air was introduced, and the discoloration of the indicator and the exudation of the reagent were observed. As a result, the discoloration of the indicator was not seen even after two months, but the reagent bleeded out and the width of the band portion increased.

[0015]

[Table 1]

[0016]

INDUSTRIAL APPLICABILITY According to the present invention, a test paper containing an acid-base indicator is enclosed together with a gas adsorbent or absorbent desiccant in a container, or the test paper is used as a gas adsorbent, a gas absorbent or a desiccant. Although it is a simple storage method of enclosing it in a container together with the container, according to the present invention, even if the test paper has high sensitivity, it does not discolor during storage or the reagent does not exude. Especially, even when the storage container is frequently used and the storage container is often opened, there is no discoloration or exudation of the reagent,
There is a great practical value as a storage method for a test strip containing an acid-base indicator.

Claims (4)

[Claims] 1. A method for storing a test strip containing an acid-base indicator, which comprises enclosing a test strip containing an acid-base indicator in a container together with a gas-adsorbing or absorbing desiccant. 2. The acid-base indicator according to claim 1, wherein the desiccant having a gas adsorbing property or an absorbing property contains at least one selected from synthetic zeolite and quicklime, or one containing these desiccants as a constituent component. How to store test paper. 3. A method for storing a test strip containing an acid-base indicator, which comprises enclosing a test strip containing an acid-base indicator in a container together with a gas adsorbent, a gas absorbent and a desiccant. 4. The gas adsorbent or gas absorbent is one or more selected from slaked lime and soda lime, and the desiccant is natural or synthetic zeolite, quick lime, silica gel, calcium chloride, magnesium chloride, calcium.
4. One or more kinds selected from silica / alumina clay or a desiccant thereof is contained as a constituent component.
A method for storing a test strip containing the acid-base indicator described in 1.