GB 1886.3-2021National food safety standard - Food additives - Calcium hydrogen phosphate (English PDF)

2.1 Molecular formula

Calcium hydrogen phosphate dihydrate. CaHPO4.2H2O

Anhydrous calcium hydrogen phosphate. CaHPO4

2.2 Relative molecular mass

Calcium hydrogen phosphate dihydrate. 172.09 (according to 2018

international relative atomic mass)

3.1 Sensory requirements

The sensory requirements shall meet the requirements of Table 1.

Annex A

Inspection methods

WARNING. Some reagents used in this test method are toxic or corrosive.

Appropriate safety and protection measures shall be taken during

operation. When necessary, it shall be carried out in a fume hood. If it

splashes on the skin, it shall be rinsed with water immediately. The severe

cases shall be treated immediately.

A.1 General

The reagents and water used in this Standard refer to analytically-pure reagents

and grade three water specified in GB/T 6682 when other requirements are not

indicated. All standard solutions, preparations and products used in the test for

impurity determination shall be prepared in accordance with the provisions of

GB/T 601, GB/T 602, and GB/T 603 when other requirements are not specified.

The solution used refers to an aqueous solution when it is not specified which

solvent is used for preparation.

A.2 Identification test

A.2.1 Reagents and materials

A.2.1.1 Hydrochloric acid solution. 1+3.

A.2.1.2 Ammonia solution. 1+1.

A.2.2 Identification method

A.2.2.1 Identification of calcium ion

Weigh about 0.1g of specimen. Add 5mL of water, 5mL of hydrochloric acid

solution to make the specimen dissolved. Add 2.5mL of ammonia solution

dropwise while shaking. Then add 5mL of ammonium oxalate solution to

generate white precipitation.

A.2.2.2 Identification of phosphate ion

Weigh about 0.1g of specimen. Add nitric acid solution dropwise until the

specimen is dissolved and then exceed by 1mL. Heat to 40°C~50°C. Add 10mL

of ammonium molybdate solution to generate yellow precipitation.

A.3 Determination of calcium hydrogen phosphate content

A.3.4.2 Determination

Accurately pipette 25mLof test solution in a 250mL Erlenmeyer flask. Add

100mL of water, 0.5mL of triethanolamine. Add 0.3g of hydroxynaphthol blue

indicator. Put it on a magnetic stirrer and stir evenly. Use a burette to add about

23mL of ethylenediaminetetraacetic acid disodium standard titration solution at

a normal speed. Add dropwise sodium hydroxide solution from red to bright blue,

and finally to purple. Then exceed by 0.5mL. Continue to use

ethylenediaminetetraacetic acid disodium standard titration solution to titrate

the solution to blue. Keep it unchanged for 60s. At the same time, conduct the

blank test.

A.7 Determination of arsenic (As)

Weigh an appropriate amount of the specimen after burning in A.4.Add

hydrochloric acid solution (1+1) dropwise until the specimen is dissolved and

then exceed by 2mL. Then determine according to the method specified in GB

5009.76 or GB 5009.11.Use hydrochloric acid (or hydrochloric acid solution)

instead of sulfuric acid (or sulfuric acid solution) in the test procedure. The water

used in the test is grade two water specified in GB/T 6682.

A.8 Determination of heavy metals (as Pb)

Weigh 2g+/-0.01g of the specimen after burning in A.4.Add 5mL of hydrochloric

acid solution (1+1), 20mL of water. Heat to dissolve. After cooling, add dropwise

ammonia solution (1+5) until white precipitation appears. Add a small amount

of hydrochloric acid solution (1+1) until the precipitation disappears. According

to the method specified in GB 5009.74, add 5mL of pH3.5 acetate buffer.

Determine. The water used in the test is grade two water specified in GB/T 6682.

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