Ehrlich's reagent

It is named after Nobel Prize winner Paul Ehrlich who used it to distinguish typhoid from simple diarrhoea.

The Ehrlich reagent works by binding to the C2 position of two indole moieties to form a resonance stabilised carbenium ion compound.

[1] Ehrlich reagent can be used to detect urobilinogen, which can indicate jaundice or other liver-related issues.

[3] Pyridoxine, present in vitamin supplements, can give positive results to the Ehrlich test, showing a pink colour change.

[8] The Ehrlich reagent is similar to a number of other indole tests:

p -DMAB: the active ingredient in Ehrlich's reagent
Ehrlich's reagent can be used to test for the presence of LSD. Upon reaction, the Ehrlich's reagent turns to purple indicating the presence of LSD. [ 2 ]