On the chemistry of Jorissen test for morphine

The Jorissen’s test for morphine employs warm sulphuric acid both as solvent and reagent. Care must be taken in order to prevent morphine-apomorphine rearrangement. The species for sulphonation derives from sulphuric acidium ion whose dehydration produces the reactive cation HSO3+. Reaction with the phenolic group in morphine gives an organic sulphate. Interaction with a hydrion and water elimination produces a key intermediate. There is separation of sulphur dioxide, ketone formation, and formation of a new sulphate at the activated C-2 position. Isomerization of dienone to phenol restores aromaticity. Finally, dehydration by acidolysis gives rise to a concerted push-pull mechanism: water, SO2, and an ortho-benzoquinone are formed. Added ferrous sulphate and ammonia water originate halochromism: red to violet colour and the ammonia turns blue.