ANSI IT4.107-2002 pdf download Processing Chemicals – Specifications for Anhydrous Citric Acid and Citric Acid Monohydrate
7.2 Mass fraction of residue after ignition
7.2.1 Specification The maximum mass fraction of residue after ignition shall be 0.05%.
7.2.2 Procedure Determine the residue after ignition in accordance with ISO 1 0349-4. Use a test portion of 1 0 g ± 0.1 g of the sample weighed to the nearest 0.1 mg and incinerate at 600 o C + 50 o C for 4 hours. Cool the residue in a desiccator and then weigh to the nearest 0.1 mg. Retain this residue for the heavy metals (7.3) and iron (7.4) tests.
7.3 Mass fraction of heavy metals
7.3.1 Specification The maximum mass fraction of heavy metals shall be 0.001 %.
7.3.2 Procedure NOTE – The standard for the iron test (7.4) is prepared in the same way as the heavy metals standard. Determine the percentage of heavy metals in accordance with ISO 1 0349-5. Use a test portion of the residue after ignition (7.2) corresponding to 4 g of the sample prepared in accordance with ISO 1 0349-5:1 992, 7.1 (i.e., 1 0 ml of the 25 ml residue solution). Use 4 ml of the heavy metals standard prepared in accordance with ISO 1 0349-5:1 992, 8.1 .1 .
7.4 Mass fraction of iron
7.4.1 Specification The maximum mass fraction of iron shall be 0.001 %.
7.4.2 Procedure Determine the percentage of iron in accordance with ISO 1 0349-5. Use a test portion of the residue after ignition corresponding to 2 g ± 0.1 g of the sample prepared in accordance with ISO 1 0349-5:1 992, 7.1 (i.e., 5 ml of the 25 ml residue solution). Use 4 ml of the iron standard prepared in accordance with ISO 1 0349-5:1 992, 8.1 .1 .
7.5 Mass fraction of halide (as Cl – )
7.5.1 Specification The maximum mass fraction of halides as Cl – shall be 0.005%.
7.5.2 Procedure Determine the percentage of halides (expressed as Cl – ) in accordance with ISO 1 0349-6.
7.6 Appearance of solution
7.6.1 Specification The prepared solution shall be clear, colorless, and free from sediment. A slight flocculence or turbidity may be disregarded. 7.6.2 Procedure Prepare a solution containing 1 00 g of anhydrous citric acid or citric acid monohydrate per liter of water. Observe the solution for clarity.