Update
The Oxford Biblical Studies Online and Oxford Islamic Studies Online have retired. Content you previously purchased on Oxford Biblical Studies Online or Oxford Islamic Studies Online has now moved to Oxford Reference, Oxford Handbooks Online, Oxford Scholarship Online, or What Everyone Needs to Know®. For information on how to continue to view articles visit the subscriber services page.
Dismiss

Related Content

More Like This

Show all results sharing these subjects:

  • Science and technology
  • Chemistry

GO

Show Summary Details

Overview

marquis test


Quick Reference

A widely used presumptive test that gives a variety of colour changes with a range of compounds. It is particularly useful for detecting opiate alkaloids and for amphetamines and methamphetamine. Marquis reagent is a mixture of methanal (formaldehyde) solution in water with sulphuric acid. Mescaline gives an orange colouration. With morphine, a violet colour is produced. Amphetamines give an orange-red colour and methamphetamine gives an orange colour. The two can be distinguished by the Simon test. The mechanism involves attack of the aldehyde an a substituted aromatic ring to form a carbocation. Further reaction forms a coloured dimer of the original molecule.


Reference entries