I am writing a book and as part of the plot one of the characters has a plant that contains alkaloids in tincture form. They want to do a test to detect for the alkaloids so they use the Dragendorff's reagent test. Quote below:

Bindweed contains alkaloids. The Dragendorff's reagent is a simple test to detect for them. They had all I needed in the chemistry lab... bismuth nitrate, hydrochloric acid, potassium iodide. When I added milk to the solution it turned orange confirming the presence of alkaloids. I did a control test too and nothing happened.

Would this technically work?

New contributor
Cari is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
  • $\begingroup$ Here is how you make Dragendorff's: this prep uses acetic acid rather than hydrochloric communities.acs.org/thread/4183 I've seen other preps that use tartaric acid. It is possible to get false positives from other plant extracts that have a basic centre researchgate.net/post/… $\endgroup$ – Waylander Jan 9 at 13:55
  • $\begingroup$ Thank you for coming back! I need to add that in my book the bindweed plant has been made into a tincture, so dissolved in alcohol, and then a few drops of it are added to a glass of milk. It is this milk that is being tested. I don't know if the Dragendorff's test would still pick up the alkaloids of the bindweed in this form? $\endgroup$ – Cari Jan 10 at 12:17
  • $\begingroup$ It should if the alkaloids have extracted into the alcohol which I think they would. You should have them run the blind of testing milk without the tincture to see if that tests positive - (also an author) $\endgroup$ – Waylander Jan 10 at 12:57

Your Answer

Cari is a new contributor. Be nice, and check out our Code of Conduct.

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.