Total acidity includes free acid, combined acid and organic acids from food or bacterial metabolism, such as lactic acid vinegar and acid phosphate.

Potentiometric titration method:

Use the pH glass electrode as the indicator electrode, the saturated calomel electrode as the reference electrode, and form a primary cell with the submerged water sample and connect it to the pH meter. Titrate the sodium hydroxide standard solution to pH meter indications of 3.7 and 8.3, and calculate the two acidities based on the corresponding consumed volumes of the sodium hydroxide standard solution.

This method is suitable for the determination of acidity of various water bodies and is not limited by the color or turbidity of water samples. When measuring, attention should be paid to the influence of factors such as temperature, stirring state, and response time.

Extended information:

Advantages of acidity:

Compared with pH, ??it has the following three obvious advantages:

1 , The larger the value of acidity is, the stronger the acidity of the solution is, which conforms to the language convention of physical definition.

2. The logarithm is a dimensionless ratio, and the return value of the logarithmic function is also dimensionless, which is in line with the characteristics of the logarithmic function.

3. No matter at any temperature, the neutral solution AG is always 0. Different from this, it is customary to assume that the pH of a neutral solution at 25 degrees Celsius is 7, and the pH of a neutral solution at other temperatures is not 7.

In addition, the value range of acidity AG is R, while the traditional value range of pH is 0 to 14.

Baidu Encyclopedia-Total Acidity

Baidu Encyclopedia-Acidity