GB 1886.338-2021National food safety standard - Food additives - Trisodium phosphate (English PDF)

2.1 Molecular formula

Trisodium phosphate anhydrous: Na3PO4 Trisodium phosphate monohydrate: Na3PO4·H2O Trisodium phosphate dodecahydrate: Na3PO4·12H2O

2.2 Relative molecular mass

Trisodium phosphate anhydrous: 163.94 (according to 2018 international relative atomic mass)

Trisodium phosphate monohydrate: 181.96 (according to 2018 international relative atomic mass)

Trisodium phosphate dodecahydrate: 380.14 (according to 2018 international relative atomic mass)

3.1 Sensory requirements

Sensory requirements shall be in accordance with Table 1.

A.1 General provisions

The reagents and water that are used in this Standard, when no other requirements are specified, refer to analytical reagents and grade-III water which is specified in GB/T 6682. The standard titration solutions, preparations and products, which are used in the test, are all prepared in accordance with GB/T 601, GB/T 602, and GB/T 603, unless other requirements are specified.

The used solution, if not indicated which solvent is used, refers to aqueous solution.

A.2 Identification test

A.2.1 Reagents and materials

A.2.1.1 Hydrochloric acid.

A.2.1.2 Acetic acid solution: 1+1.

A.2.1.3 Ammonia solution: 2+3.

A.2.1.4 Silver nitrate solution (17 g/L).

A.2.1.5 Platinum wire ring.

A.2.2 Identification method

A.2.2.1 Sodium ion

Weigh 1 g of the sample; add 20 mL of water to dissolve. After wetting the platinum wire ring with hydrochloric acid, burn it to colorless on a colorless flame.

Dip the test solution again and burn in a colorless flame. The flame shall be bright yellow.

A.2.2.2 Phosphate ion

Weigh 0.1 g of the sample; dissolve it in 10 mL of water; add 1 mL of silver nitrate solution, to produce yellow precipitate. This precipitate is soluble in ammonia solution, and insoluble in acetic acid solution. […]

A.5 Determination of water insoluble matter

A.5.1 Instruments and apparatuses

A.5.1.1 Glass sand crucible: The aperture of the filter plate is 5 µm ~ 15 µm.

A.5.1.2 Electrothermal constant-temperature dry box: The temperature control range is 105 °C ± 2 °C.

A.5.2 Analysis steps

Weigh about 20 g of the sample, accurate to 0.01 g; place it in a 400 mL beaker; add 200 mL of water; heat to dissolve it. While it is hot, use a glass sand crucible that has been dried to constant mass at 105 °C ± 2 °C to filter; use hot water to wash it until the filtrate is alkali-free. Place the glass sand crucible and water-insoluble matter in an electrothermal constant-temperature dry box at 105 °C ± 2 °C to dry until the mass is constant.

A.5.3 Result calculation

Calculate the mass fraction w3 of the water insoluble matter according to Formula (A.5).

Where: m4 - mass of the water insoluble matter and the glass sand crucible, in grams (g); m5 - mass of the glass sand crucible, in grams (g); m6 - sample mass, in grams (g).

The test result is based on the arithmetic mean of the parallel determination results. The absolute difference between two independent determination results that are obtained under repeatability conditions is not more than 0.02%.

A.6 Determination of pH (10 g/L solution)

A.6.1 Reagents and materials

Carbon dioxide-free water. […]

A.6.2 Instruments and apparatuses