What is Ehrlich's Test used for?

Ehrlich's Test is specifically designed to identify the presence of indole compounds, which makes it particularly effective for detecting LSD (lysergic acid diethylamide). This test works by reacting with the indole ring present in LSD, producing a color change that indicates the presence of this substance. The significance of this test lies in its applicability to substances that contain indoles, allowing for a rapid screening method for LSD in suspected samples.

The other options pertain to drugs that do not contain indole structures, making Ehrlich's Test unsuitable for their detection. Each of these substances requires different testing methods or reagents to confirm their presence, emphasizing the specificity of Ehrlich's Test for LSD.