Ph value testing liquid and preparation method thereof

Abstract

The invention discloses a pH value testing liquid with the testing range of 4.6-7.6 and a preparation method of the pH value testing liquid. The invention provides a testing liquid which is convenient in testing, rapid in developing, good in stability and hard to splash and leak, and a preparation method of the testing liquid. The testing liquid comprises the following components by weight percent: 50-60% of an organic solvent, 0.5-3% of a thickening agent, 0.5-1% of an antioxidant, 1-2% of ethoxychrysoidine, 2-3% of litmus, 0.5-1% of bromcresol purple, 0.5-1% of neutral red, 0.2-0.5% of methylene blue and the balance of distilled water. After the testing liquid is used, the gradient change of agent color can be displayed when the accuracy change of the pH value difference which can be observed visually is 0.2; the testing liquid is convenient in testing, rapid in developing, good in stability, hard to splash and leak and low in price, is suitable for the quick test in the pH value change range outside a laboratory, and can be used in the fields of food safety, medicine detection, environmental protection, water quality monitoring, industrial production, criminal assay and the like which need to rapidly and accurately testing the pH value of solution to be tested outside the laboratory.

Description

technical field [0001] The invention relates to the technical field of chemical analysis, in particular to a pH value test solution with a test range of 4.6-7.6 and a preparation method thereof. Background technique [0002] The pH value of a solution represents the H in the solution + and OH - The concentration of ions, abbreviated as pH value, is a quantitative index to measure the degree of acidity and alkalinity of a solution, which is defined as the H in the solution + The negative logarithm of the concentration. The lower the pH, the stronger the acid, and the higher the pH, the stronger the alkaline. The pH value of a solution is the most basic indicator in analytical chemistry and often needs to be measured. From the definition of pH value, it can be known that pH value is a scale to measure the acidity and alkalinity of a solution, and it is necessary to control the acidity and alkalinity of a solution in many aspects. Therefore, an accurate and convenient test ...

AI Technical Summary

Problems solved by technology

Because the color range is too narrow, the pH value exceeds the measurement range and cannot be measured, which limits its application. At the same time, there are also problems such as difficult to observe the color, poor stability and easy to leak.

In addition, the test solution prepared by multi-component color reagents, such as the test solution with a pH value of 4 to 10 in the market, has an unknown formula. During use, the color development effect of this test solution from different purchase sources is roughly the same. Only the difference in the concentration of the drug solution

When measuring the pH value of the solution to be tested, the naked eye can barely observe the color change of the chromogenic agent when the pH is at an accuracy of 0.5, and some color intervals can be barely observed at an accuracy of pH 1.0; the display of various components The solvent of the test solution prepared by the color reagent is a mixed solvent of water and ethanol. Due to the volatile nature of ethanol, its volume gradually decreases during storage. Therefore, it will be found that the solution will decrease after several months of use, and solute precipitation and oxidation will occur. Deterioration phenomenon, at the same time, there will be more serious leakage during the transfer and transportation process

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