1. A method for detecting the content of sodium carbonate in washing powder is characterized by comprising the following steps: the method comprises the following steps:

A. measuring the quality of a hydrochloric acid reagent and a washing powder sample to be measured;

B. pouring a hydrochloric acid reagent into the open container, and communicating the pressure gauge with the open container;

C. putting the washing powder to be detected into the open container and then sealing the open container;

D. shaking the open container to pour the washing powder sample to be detected out of the bag or to enable the hydrochloric acid reagent to enter the bag, and reacting sodium carbonate in the washing powder sample to be detected with the hydrochloric acid reagent;

F. and reading the pressure value of the pressure gauge, and calculating the sodium carbonate content of the washing powder sample by a formula.

2. The method for detecting the content of sodium carbonate in washing powder according to claim 1, wherein the method comprises the following steps: the open container is a two-neck flask or a three-neck flask.

3. The method for detecting the content of sodium carbonate in washing powder according to claim 1, wherein the method comprises the following steps: the step C further comprises the following steps: and putting the sample into a bag, and sealing the open container after putting the bag into the open container, wherein the bag is made of a material which does not react with the hydrochloric acid reagent.

Background

At present, the washing powder total analysis and inspection is time-consuming and labor-consuming, so that internal organizations of departments review and carding related inspection methods. According to the method, according to the principle of an acid-base titration method, the end points of phenolphthalein and methyl orange indicators are respectively titrated by hydrochloric acid standard solution for the whole part of a detergent sample solution, and then the sodium carbonate content is calculated by back-titrating the sodium hydroxide standard solution to the end point of the phenolphthalein indicators. The method takes 40 minutes, is not beneficial to control adjustment and quality control in a workshop, and needs to find a detection method with higher efficiency for improving the detection efficiency.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a method for detecting the content of sodium carbonate in washing powder, which solves the problem of long detection time of a washing powder sodium carbonate content detection project.

The invention is realized by the following technical scheme:

a method for detecting the content of sodium carbonate in washing powder comprises the following steps:

A. measuring the quality of a hydrochloric acid reagent and a washing powder sample to be measured;

B. pouring a hydrochloric acid reagent into the open container, and communicating the pressure gauge with the open container;

C. putting the washing powder to be detected into the open container and then sealing the open container;

D. shaking the open container to pour the washing powder sample to be detected out of the bag or to enable the hydrochloric acid reagent to enter the bag, and reacting sodium carbonate in the washing powder sample to be detected with the hydrochloric acid reagent;

F. and reading the pressure value of the pressure gauge, and calculating the sodium carbonate content of the washing powder sample by a formula.

Wherein, the open container is a two-neck flask or a three-neck flask.

Wherein, the step C further comprises: and putting the sample into a bag, and sealing the open container after putting the bag into the open container, wherein the bag is made of a material which does not react with the hydrochloric acid reagent.

The invention has the beneficial effects that:

the problem of longer detection time of a washing powder sodium carbonate content detection project is solved: according to the method for detecting the content of the sodium carbonate in the washing powder, the sodium carbonate in the washing powder reacts with the hydrochloric acid to generate carbon dioxide with a fixed volume, the generated carbon dioxide can increase the air pressure in the closed container, and the content of the sodium carbonate in the washing powder can be converted through a formula. Compared with the traditional acid-base titration method, the detection method has the advantages of higher detection speed and higher efficiency, and the accuracy of the detection result is similar to that of the acid-base titration method.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.

FIG. 1 shows the gas pressure after the reaction of hydrochloric acid and sodium carbonate in a closed container.

FIG. 2 is a graph showing deviation between the test results of the present invention and the test results of the acid-base titration method.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

The method comprises the steps of titrating the whole part of a detergent sample solution with a hydrochloric acid standard solution to obtain phenolphthalein and methyl orange indicators, and then titrating the whole part of the detergent sample solution with a sodium hydroxide standard solution to obtain the phenolphthalein indicators, and calculating the content of sodium carbonate. The reaction formula of the reaction is as follows:

Na₂CO₃+HCl----NaHCO₃+H₂0+CO₂，

NaHCO₃+H₂0+CO₂----NaCl+H₂0+CO₂。

the embodiment discloses a method for detecting the content of sodium carbonate in washing powder, which comprises the following steps:

A. measuring the quality of a hydrochloric acid reagent and a washing powder sample to be measured;

B. pouring a hydrochloric acid reagent into the open container, and communicating the pressure gauge with the open container;

C. putting the washing powder to be detected into the open container and then sealing the open container;

D. shaking the open container to pour the washing powder sample to be detected out of the bag or to enable the hydrochloric acid reagent to enter the bag, and reacting sodium carbonate in the washing powder sample to be detected with the hydrochloric acid reagent;

F. and reading the pressure value of the pressure gauge, and calculating the sodium carbonate content of the washing powder sample by a formula.

The formula of the reaction between the sodium carbonate in the washing powder to be detected and the hydrochloric acid reagent is as follows:

Na₂CO₃+HCl----NaCl+H₂0+CO₂。

from the law of conservation of mass, at a given mass of Na₂CO₃After then, CO₂The discharge amount of (2) is constant, and a glass two-necked flask or a glass three-necked flask having good sealing property and no risk of gas leakage or instability of pressure value is selected as an open vessel for detecting the gas pressure on the basis of the principle of detection by the gas pressure method, and a pressure gauge having a range of 0 to 300mmHg is selected on the basis of the pressure value.

The conversion of the content of sodium carbonate in the washing powder and the air pressure value can be realized by firstly reacting soda ash with different mass with a hydrochloric acid reagent. In this example, 0g, 0.1g, 0.15g, 0.20g, 0.25g, 0.30g, 0.35g, 0.40g, 0.45g, 0.50g of soda ash were weighed and placed in an open container to react with the hydrochloric acid reagent, the value of the pressure gauge was read, the pressure value was taken as the ordinate, the sodium carbonate mass was taken as the abscissa, the standard curve y ═ kx was obtained, and it was found that k is a constant, and the specific test curve was prepared as shown in fig. 1. And then, according to the detection method disclosed in the embodiment, reading the pressure value of the pressure gauge, and substituting the pressure value into the standard curve, so as to obtain the content of sodium carbonate in the current washing powder to be detected.

In practical use, step C specifically comprises: and putting the sample into a bag, and sealing the open container after putting the bag into the open container, wherein the bag is made of a material which does not react with the hydrochloric acid reagent.

The aim of the method is to ensure that the washing powder does not react with a hydrochloric acid reagent when being put into the open container, and the washing powder reacts after the open container is completely closed, thereby reducing or even avoiding CO₂Overflow from the open container makes the test result more accurate. The deviation of the test results of this example from those of the acid-base titration method is shown in FIG. 2, and the absolute deviation of the two replicates should not exceed 0.5%.

In conclusion, according to the method for detecting the content of sodium carbonate in the washing powder, carbon dioxide with a fixed volume is generated through the reaction of the sodium carbonate in the washing powder and hydrochloric acid, the generated carbon dioxide can increase the air pressure in the closed container, and the content of the sodium carbonate in the washing clothes can be converted through a formula. Compared with the traditional acid-base titration method, the detection method has the advantages of higher detection speed and higher efficiency, and the accuracy of the detection result is similar to that of the acid-base titration method.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.