What is ehlrich reagent?

Ehrlich reagent is a chemical test used to detect the presence of indoles (a class of organic compounds) such as tryptophan, serotonin, and psilocin/pilocin in a substance. The reagent turns purple when it comes in contact with indoles. Arthur Ehrlich discovered the reagent in 1883 and it is made of p-dimethylaminobenzaldehyde and hydrochloric acid. This test is commonly used to identify the presence of indole-containing compounds in drugs or in forensic toxicology. However, the test can produce false positives or negatives, and it cannot distinguish between different types of indoles. Therefore, it is often used in combination with other tests to confirm the results.