National Food Safety Standard
Food Contact Materials and Articles
Determination of Potassium Permanganate Consumption
食品安全国家标准 食品接触材料及制品
高锰酸钾消耗量的测定
1 Scope
This standard specifies the determination method of potassium permanganate consumption in food contact materials and articles.
This standard is applicable to the determination of potassium permanganate consumption in food contact materials and articles.
2 Theory
Titrate the specimen soak solution with potassium permanganate standard solution under acidic condition, and calculate the potassium permanganate consumption in the specimen according to the volume of titration solution consumed by the specimen.
3 Reagents and Materials
Unless otherwise specified, all reactants adopted for this method are analytically pure and water is Grade 2 water as specified in GB/T 6682.
3.1 Reactants
3.1.1 Sulfuric acid (H2SO4).
3.1.2 Potassium permanganate (KMnO4).
3.2 Preparation of reagents
3.2.1 Sulfuric acid solution (1+2): pipet 100mL of sulfuric acid, pour it into 200mL of water carefully, and then mix the solution well.
3.2.2 0.04% potassium permanganate solution: weigh 0.4g of potassium permanganate, dissolve it in water to 1,000mL.
3.2.3 Oxalic acid standard solution [c( H2C2O4)=0.1mol/L]: prepare and calibrate the solution according to GB/T 601 or purchase commercialized product.
3.2.4 Oxalic acid standard titration solution [c( H2C2O4)=0.01mol/L]: pipet 10.0mL of oxalic acid standard solution [c( H2C2O4)=0.1mol/L] into a 100mL volumetric flask, and dilute with water to the scale.
3.3 Standards
Potassium permanganate standard solution [c( KMnO4)=0.1mol/L]: prepare and calibrate the solution according to GB/T 601 or purchase commercialized product.
3.4 Preparation of standard solution
Potassium permanganate standard titration solution [c( KMnO4)=0.01mol/L]: pipet 10.0mL of potassium permanganate standard solution [c( KMnO4)=0.1mol/L] into a 100mL volumetric flask, and dilute with water to the scale.
4 Analytical Procedures
4.1 Sampling method
Operate according to GB/T 5009.156.
4.2 Specimen washing
Operate according to GB/T 5009.156.
4.3 Selection of food simulants and simulation conditions of the specimen
Operate according to corresponding product standard.
4.4 Pretreatment method for specimen migration test
Operate according to GB/T 5009.156.
4.5 Determination of specimen
4.5.1 Treatment of conical flask
Pipet 100mL of water into a 250mL conical flask, then add 5mL of sulfuric acid (1+2) and 5mL of 0.04% potassium permanganate solution, boil the solution for 5min, then pour the solution out, and wash the conical flask with water for use in the next step.
4.5.2 Titration
Accurately pipet 100mL of water soak solution (sampling quantity may be adjusted according to the actual situation) into the above-mentioned treated 250mL conical flask, add 5mL of sulfuric acid (1+2) and 10.0mL of potassium permanganate standard titration solution (0.01mol/L), then add two glass beads, boil the content for 5min accurately, then add 10.0mL of oxalic acid standard titration solution (0.01mol/L) while the content is hot, and titrate the solution with potassium permanganate standard titration solution (0.01mol/L) until the solution becomes into reddish color and also does not fade within 0.5min, and record the final consumed volume of potassium permanganate standard titration solution.
Pipet another 100mL of water and carry out reagent blank test.
5 Expression of Analysis Results
5.1 The potassium permanganate consumption in the specimen shall be calculated according to Formula (1):
(1)
Where,
X1 - the potassium permanganate consumption in the specimen, mg/dm2;
V1 - the volume of potassium permanganate solution consumed for titrating the specimen soak solution, mL;
V2 - the volume of potassium permanganate solution consumed for titrating the reagent blank, mL;
c - the actual concentration of potassium permanganate standard titration solution, mol/L;
31.6 - the mass of potassium permanganate equivalent to 1.00mL of potassium permanganate standard titration solution [c( KMnO4)=1.000mol/L], mg;
V - the total volume of specimen soak solution, mL;
V3 - the volume of soak solution used for determination, mL;
S - the contact area between specimen and soak solution, dm2.
5.2 When the potassium permanganate consumption in the specimen is calculated according to the actual use situation, it shall be calculated according to Formula (2):
(2)
Where,
X2 - the potassium permanganate consumption in the specimen calculated according to the actual use situation, mg/L or mg/kg;
X1 - the potassium permanganate consumption in the specimen, mg/dm2;
S2 - the actual packaging contact area of specimen, dm2;
V4 - the actual packaging contact volume or mass of specimen, mL or g;
1000 - the conversion coefficient.
The calculation result is expressed by the arithmetic mean value of two independent determination results under repeatability conditions and retained with two significant figures.
Foreword I
1 Scope
2 Theory
3 Reagents and Materials
4 Analytical Procedures
5 Expression of Analysis Results
6 Precision
