Prepared at the 19th JECFA (1975), published in NMRS 55B (1976) and in S.
To 10 ml of a 1 in 10 solution of the sample add 1 ml of mercuric sulfate TS. Heat the mixture to boiling and add a few drops of potassium permanganate TS. A white precipitate is formed. Test for potassium When hydrochloric acid is present, a solution of the sample gives with platinum chloride TS a yellow crystalline precipitate (which on ignition leaves a residue of potassium chloride and platinum).PURITY
Loss on drying (Vol. 4) Not more than 6% (180o, 4 h)
Alkalinity A 1 in 20 solution of the sample is alkaline to litmus. After the addition of ml of N sulfuric acid and 1 drop of phenolphthalein TS to 10 ml of the solution no pink colour is produced.
Oxalate To 10 ml of a 1 in 10 solution of the sample add 5 drops of dilute acetic acid TS and 2 ml of calcium chloride TS. No turbidity develops within 1 h.
Lead (Vol. 4) Not more than 2 mg/kg Determine using an atomic absorptio