In general, we use the method of titration to test the content of potassium citrate in the food additive potassium citrate. To understand the potassium citrate products as acidity regulator, stabilizer and coagulator and quality improver in the food industry. We can according to the principle of chemical: glacial acetic acid as solvent, crystal violet as the indicator, with perchloric acid standard solution titration to test by purple turned blue end, in the form of anhydrous calculated its content.
Chemical name: 2-, 2, 3, three,, carboxylic acid, potassium
Molecular formula: C6H5K3O7 and H2O
COOK - CH2
|
Structural formula: C - COOK - HO - H2O
|
COOK - CH2
Relative molecular weight: 324.41
Appearance：
White or slightly yellow crystalline or crystalline powder.
Food additive potassium citrate should meet the requirements of the following table:
Project
Index
Potassium citrate (dry) content (in C6H5K3O7),%
More than
Ninety-nine
alkalinity
Through experiment
Arsenic (in As),%
Less than or equal to
Zero Point Zero Zero Zero three
Heavy metal (in Pb),%
Less than or equal to
Zero point zero zero one
Dry weight loss,%
3 ~ 6
Operation steps:
Weigh about 0.25g to 180 plus or minus 2 DEG C drying sample, accurate to 0.0002g, placed in a dry 250ml conical flask, plus 40ml glacial acetic acid, slightly heating, dissolving, cooling to room temperature, add 2 drops of crystal violet indicator solution, with perchloric acid titrant to the solution from purple variable blue as the end point. At the same time to do a blank test.
Result calculation
Calculation of the content of potassium citrate in the sample:
X = (-V2 V1) * c * 0.1021 * 100
M
Formula: X - content of potassium citrate in the sample,% (m/m); V1 - sample consumption of the volume of the standard solution of hydrochloric acid, mL;
V2 - Blank Test consumes the volume of standard solution of hydrochloric acid, mL; C -- the concentration of standard solution of high acid, mol/L;
LG - and ~ perchloric acid titration solution [C (HClO 4) =1.000mol/L] quite, expressed in grams of potassium citrate quality;
M - the quality of the sample, G.
Precision degree:
The arithmetic mean of the two parallel test results is the result, and the absolute difference of the parallel test result is no more than 0.2% of the average value.
Mark:
Packing bag should be firm and clear sign, should specify the production factory name, the site of factory, product name, trademark, the standard number, batch number, production date, weight and "food additive" words.
Name of manufacturer
Lianyungang Shuren Kechuang Food Additive Co.
Site of a factory
Jiangsu city in Lianyungang Province Economic and Technological Development Zone Dapu Industrial Zone Linhong Road No. 22
Product name
Potassium citrate
trademark
Treant
This standard number
GB2010
Net weight
25kg/ bag
Packing：
Food additives, potassium citrate, lined with food grade polyethylene film and double layer kraft paper or double layer food grade polyethylene film bag for inner packaging, outer packaging plastic woven bag. The net weight of each bag is 25kg, the allowable error is + 0.5%, but also can be packed according to the user's needs.
Transportation and storage:
Transport should be kept in a complete package, waterproof, moisture, and is prohibited from mixing with toxic materials and mix, should be stored in a cool, dry and ventilated place.
This product from the date of delivery in line with the provisions of this standard storage conditions, storage period of one year or two years, etc..