What is the standard solution of COD max ll hashing reagent?

In fact, the bottle of standard solution is not a fixed standard value, but a potassium hydrogen phthalate solution. When the instrument is tested, it will automatically absorb a certain proportion of distilled water and mix it with a certain proportion of potassium hydrogen phthalate solution to get the COD value. The following is the solution configuration method for your reference.

Zero standard solution:

500 ml distilled water

Ethyl sulfuric acid, 95~97% ACS 0.5 ml.

1. First, add 400 ml of distilled water to a 500 ml measuring cylinder.

2. During mixing with a magnetic stirring bar, carefully add 0.5 ml of compound B (sulfur

Acidity 95~97% ACS).

3. After mixing, add distilled water until the scale reaches 500mL.

Standard solution:

Potassium hydrogen phthalate 500 ml

Ethyl sulfuric acid, 95~97% ACS 0.5 ml.

1. Add 200ml distilled water into a 250ml measuring cup.

2. In the process of stirring with a magnetic stirrer, carefully add 0.31875g of substance A (near.

Potassium hydrogen benzoate) and substance B (95-97% ACS sulfate).

3. After potassium hydrogen phthalate is completely dissolved (the solution is clear), add distilled water to 250 ml.

Remarks: Before using potassium hydrogen phthalate, please put it in 105℃ oven to dry.