How to test the addition of inorganic substances i

How to test the addition of inorganic substances in ACR processing aids：

Detection method for Ca2+:

Experimental instruments and reagents: beaker; Cone shaped bottle; Funnel; burette; Electric furnace; Anhydrous ethanol; Hydrochloric acid, NH3-NH4Cl buffer solution, calcium indicator, 0.02mol/L EDTA standard solution.

Test steps:

1. Accurately weigh a certain amount of ACR processing aid sample (accurate to 0.0001g) and place it in a beaker. Wet it with anhydrous ethanol, then add excess 1:1 hydrochloric acid and heat it on an electric furnace to completely react calcium ions with hydrochloric acid;

2. Wash with water and filter through a funnel to obtain the clear liquid;

3. Adjust the pH value to be greater than 12 with NH3-NH4Cl buffer solution, add an appropriate amount of calcium indicator, and titrate with 0.02mol/L EDTA standard solution. The endpoint is when the color changes from purple red to pure blue;

4. Conduct blank experiments simultaneously;

5. Calculate C # a2+=0.02 $(V-V0) $0.04004M $%&&

V – The volume (mL) of EDTA solution consumed when testing ACR processing aid samples.

V # – Volume of solution consumed during blank experiment

M – Weigh the mass (g) of the ACR processing aid sample.

Burning method for measuring inorganic substances:

Experimental instruments: analytical balance, muffle furnace.

Test steps: Take 0.5,1.0g ACR processing aid samples (accurate to 0.001g), place them in a 950 constant temperature muffle furnace for 1 hour, cool down, and weigh to calculate the remaining burn residue. If inorganic substances are added to ACR processing aid samples, there will be more residue.