GB 1886.214-2016National food safety standard - Food additives - Calcium carbonate (including light and heavy calcium carbonate) (English PDF)

2.1 Molecular formula

CaCO3

2.2 Relative molecular mass

100.09 (according to the international relative atomic mass in 2013)

3.1 Sensory requirements

Sensory requirements shall comply with Table 1.

Table 1 -- Sensory requirements

Item Requirements Testing methods

Color White or grey white Take an appropriate amount of specimen in a 50 mL beaker, to observe the color and state in natural light State Powder

3.2 Physical-chemical indicators

Physical-chemical indicators shall meet the requirements of Table 2.

Table 2 -- Physical-chemical indicators

Item Indicators Testing methods

Content of calcium carbonate (CaCO3) (on a dry basis), w/% 98.0 ~ 100.5 A.4 in Appendix A

Insoluble of hydrochloric acid, w/%, <= 0.2 A.5 in Appendix A

Free base Pass the test A.6 in Appendix A

Appendix A

Testing method

A.1 Warning

Some of the reagents used in the test methods of this standard are toxic or corrosive, so during operation, it shall take appropriate safety and protective measures.

A.2 General requirements

The reagents and water used in this standard refer to, when no other requirements are indicated, the analytical pure reagents and the grade-3 water as specified in GB/T 6682. The standard solution, standard solution for determination of impurities, reagents and preparations as required in the test of this standard, when no other requirements are indicated, shall be prepared according to the provisions of GB/T 601, GB/T 602, GB/T 603. When the reagents which are used to prepare the solution used are not specified, the solution refers to aqueous solution.

A.3 Identification test

A.3.1 Identification of calcium

Take a small amount of specimen. Add hydrochloric acid solution (1 + 2) to dissolve it. Use phenolphthalein solution (10 g/L) as an indicator solution. Use ammonia solution (1 + 3) to adjust to neutral. Add ammonium oxalate solution (35 g/L) to produce a white precipitate, which is soluble in the hydrochloric acid solution (1 + 2) but insoluble in glacial acetic acid.

A.3.2 Identification of carbonate

Take a small amount of specimen. Add hydrochloric acid solution (1 + 2) to generate a gas. Lead this gas into calcium hydroxide solution (3 g/L). A white precipitate is produced.

A.4 Determination of calcium carbonate (CaCO3) content (on a dry basis)

A.4.1 Reagents and materials

A.4.1.1 Hydrochloric acid solution: 1 + 1.

A.4.1.2 Sodium hydroxide solution: 100 g/L.

A.4.1.3 Triethanolamine solution: 1 + 3.

(CaCO3) = 100.09];

m1 - Mass of the specimen, in grams (g);

25 - Volume of the specimen solution as pipetted, in milliliters (mL);

250 - Volume of the volumetric flask, in milliliters (mL);

1000 - Conversion factor.

The test results are based on the arithmetic mean of the parallel determination results. The absolute difference between the two independent determinations as obtained under repetitive conditions is not more than 0.2%.

A.5 Determination of hydrochloric acid insoluble

A.5.1 Reagents and materials

A.5.1.1 Hydrochloric acid solution: 1 + 1.

A.5.1.2 Silver nitrate solution: 10 g/L.

A.5.2 Instruments and equipment

High-temperature furnace: It can control the temperature at 800 °C ± 25 °C.

A.5.3 Analytical procedures

Weigh approximately 5 g of the specimen, accurate to 0.01 g. Place it in a tall beaker. After adding water to wet it, slowly add 25 mL of hydrochloric acid solution. Heat to boil it. When it is still hot, use medium-speed quantitative filter paper to filter it. Use hot water to rinse the beaker. Rinse the filter paper until the filtrate has no chloride ions (use silver nitrate solution to check it). Transfer the filter paper together with the insoluble into a porcelain crucible which had been burned at 800 °C ± 25 °C to a constant mass. After ashing it on an electric furnace, burn it at 800 °C ± 25 °C until the mass is constant.

A.5.4 Calculation of results

The mass fraction of hydrochloric acid insoluble, w2, is calculated according to formula (A.2):

Where:

m3 - The mass of hydrochloric acid insoluble and crucible, in grams (g);

In a water bath, heat it for 1 h. After cooling it, transfer it all into a 100 mL volumetric flask. Add water to the mark. Shake it uniformly. Place it overnight.

Perform dry filtration. Pipette 50 mL of the filtrate. Place it in a porcelain crucible that has been burned at 800 °C ± 25 °C to a constant mass. Add 0.5 mL of sulfuric acid. Evaporate it dry. Burn it at 800 °C ± 25 °C until the mass is constant.

A.7.4 Calculation of results

The mass fraction of magnesium and alkali metal content, w3, is calculated according to formula (A.3):

Where:

m5 - The mass of the crucible and residue, in grams (g);

m6 - The mass of the empty crucible, in grams (g);

m7 - The mass of the specimen, in grams (g);

50 - The volume of the specimen solution as pipetted, in milliliters (mL);

100 - The volume of the volumetric flask, in milliliters (mL).

The test results are based on the arithmetic mean of the parallel determination results. The absolute difference between the two independent determinations as obtained under repetitive conditions is not more than 0.2%.

A.8 Determination of loss on drying

A.8.1 Instruments and equipment

A.8.1.1 Electrothermal drying oven: The temperature can be controlled at

200 °C ± 5 °C.

A.8.1.2 Weighing bottle: Phi40 mm x 25 mm.

A.8.2 Analytical procedures

Use a weighing bottle which had been dried to constant weight at 200 °C ± 5 °C to weigh about 2 g of the specimen, accurate to 0.0002 g. Dry it at 200 °C ±

5 °C for 4 h. Cool it to room temperature. Weigh it, accurate to 0.0002 g.

A.8.3 Calculation of results

The mass fraction of the loss on drying, w4, is calculated according to the

A.10.1 Summary of method

After the specimen is treated, the cadmium ions are led into the atomic absorption spectrometer in the acidic solution. After atomization, the 228.8 nm resonance line is absorbed, the absorption amount is proportional to the cadmium content, which is compared with the standard series for quantification.

A.10.2 Reagents and materials

A.10.2.1 Hydrochloric acid solution: 1 + 4.

A.10.2.2 Cadmium standard solution: 1 mL solution contains 0.001 mg of

cadmium (Cd). Pipette 1 mL of the cadmium standard solution as prepared in

GB/T 602. Transfer it to a 100 mL volumetric flask. Add water to the mark. Shake it uniformly. Prepare it before use.

A.10.3 Instruments and equipment

Atomic absorption spectrophotometer.

A.10.4 Analytical procedures

A.10.4.1 Preparation of test solution and blank test solution

Weigh 1.00 g ± 0.01 g of specimen. Place it in a 150 mL beaker. Use water to wet it. (Cover the watch glass). Add hydrochloric acid solution dropwise to dissolve it. Heat to boil it. Cool it down. Transfer it all in to a 50 mL volumetric flask. Use water to dilute it to the mark. Meanwhile prepare the blank test solution.

A.10.4.2 Production of working curves

Pipette 0.00 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL of cadmium standard solution into six 50 mL volumetric flasks. Respectively pipette 5 mL of hydrochloric acid solution. Use water to dilute it to the mark. Shake it uniformly.

This series of solutions is the standard working solution of cadmium. Use an acetylene-air flame. Adjust the atomic absorption spectrophotometer to the optimum working condition at a wavelength of 228.8 nm. Use water as a reference, measure the absorbance. Use the mass of cadmium as the abscissa and the absorption value as the ordinate, to draw the working curve.

A.10.5 Determination

For the test solution and the blank test solution, follow the A.10.4.2 from “Use acetylene-air flame,... to measure the absorbance” to carry out operation.

Determine its absorption value. Check the mass of the cadmium from the working curve.

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