Table E.7.
Specifications established for tripotassium phosphate (E 340(iii)) according to Commission Regulation (EU) No 231/2012 and JECFA (2006a)
| Commission Regulation 231/2012 | JECFA (2006b,c,d,e,f) | |
|---|---|---|
| Assay |
Content not less than 97% calculated on the ignited basis P2O5 content between 30.5% and 34.0% on the ignited basis |
Not less than 97.0% of K3PO4, calculated on the ignited basis |
| Description | Colourless or white, odourless hygroscopic crystals or granules. Hydrated forms available include the monohydrate and trihydrate | Colourless or white, odourless hygroscopic crystals or granules; hydrated forms available include the monohydrate and trihydrate |
| Identification | ||
| Test for potassium | Passes test | To a 1 in 100 solution of the sample add 1 volume of saturated sodium hydrogen tartrate solution and 1 volume of ethanol and shake. A white crystalline precipitate is formed |
| Test for phosphate | Passes test | To 5 mL of a 1 in 100 solution of the sample add 1 mL of concentrated nitric acid and 5 mL of ammonium molybdate TS and warm. A bright canary‐yellow precipitate is obtained |
| Solubility | Freely soluble in water. Insoluble in ethanol | Freely soluble in water; insoluble in ethanol |
| pH | Between 11.5 and 12.3 (1% solution) | 11.5–12.5 (1 in 100 solution) |
| Test for orthophosphate | – | Dissolve 0.1 g of the sample in 10 mL water, acidify slightly with dilute acetic acid TS and add 1 mL of silver nitrate TS. A yellow precipitate is formed |
| Purity | ||
| Loss on ignition | Anhydrous: not more than 3.0%; hydrated: not more than 23.0% (determined by drying at 105°C for 1 h and then ignite at about 800 ± 25°C for 30 min) |
Anhydrous: Not more than 3% (120°C, 2 h, then 800°C, 30 min) Hydrated: Not more than 23% (120°C, 2 h, then 800°C, 30 min) |
| Water‐insoluble matter/substances | Not more than 0.2% (on the anhydrous basis) | Not more than 0.2% |
| Fluoride | Not more than 10 mg/kg (expressed as fluorine) |
Not more than 10 mg/kg See description under TESTS |
| Arsenic | Not more than 1 mg/kg | Not more than 3 mg/kg (Method II) |
| Cadmium | Not more than 1 mg/kg | – |
| Lead | Not more than 1 mg/kg | Not more than 4 mg/kg |
| Mercury | Not more than 1 mg/kg | – |