E 450 (v) TETRAPOTASSIUM DIPHOSPHATE
| Synonyms | Tetrapotassium pyrophosphate |
| Definition | |
|---|---|
| Einecs | 230-785-7 |
| Chemical name | Tetrapotassium diphosphate |
| Chemical formula | K4P2O7 |
| Molecular weight | 330,34 (anhydrous) |
| Assay | Content not less than 95 % (800 °C for 0,5 hours) P2O5 content not less than 42,0 % and not more than 43,7 % on the anhydrous basis |
| Description | Colourless crystals or white, very hygroscopic powder |
| Identification | |
| Test for potassium | Passes test |
| Test for phosphate | Passes test |
| Solubility | Soluble in water, insoluble in ethanol |
| pH | Between 10,0 and 10,8 (1 % solution) |
| Purity | |
| Loss on ignition | Not more than 2 % (105 °C, 4 hours then 550 °C, 30 minutes) |
| Water insoluble matter | Not more than 0,2 % |
| Fluoride | Not more than 10 mg/kg (expressed as fluorine) |
| Arsenic | Not more than 1 mg/kg |
| Cadmium | Not more than 1 mg/kg |
| Lead | Not more than 1 mg/kg |
| Mercury | Not more than 1 mg/kg |