Patent blue is a sodium compound of ammonium hydroxide belonging to the family of triarylmethane.
Synonyms: C.I.Food Brown #5
| No. | Molecular Description | Composition |
| 1. | Total colour/Assay, percent by Mass, min. | 85.00 |
| 2. | Water-insoluble matter, percent by mass, Max. | 00.20 |
| 3. | Combined ether extracts, percent by mass, Max. | 00.20 |
| 4. | Subsidiary dyes, percent by mass, Max. | 02.00 |
| 5. | Dye intermediates, percent by mass, max. Leuco base. |
00.50 04.00 |
| 6. | Unsulfonated primary aromatic amine (calculated as aniline) percent by mass, max. | 0.01 |
| 7. | Lead, mg/kg, Max. | 10 |
| 8. | Arsenic, mg/kg, Max. | 3 |
| 9. | Heavy metals, (as pb) mg/kg, max | 40 |
| 10 | Mercury, mg/kg ,Max. | 01.00 |
| 11 | Cadmium, mg/kg, Max. | 01.00 |