Timm-i Posted January 20, 2009 Share Posted January 20, 2009 Does anyone know the name of the chemical which is a colourless dye, until it reacts with the Amino acids on your skin? Which then causes it to turn a purple colour? Link to comment Share on other sites More sharing options...
bob000555 Posted January 20, 2009 Share Posted January 20, 2009 (edited) Well phenolphthalein is used to test for the presence of blood if thats what your talking about. The process is not quite as simple as is shown on shows like CSI however. First the sample is obtained then a drop of alcohol is added then several drops of phenolphthalein then a few drops of hydrogen peroxide if blood is present the sample turns pink. It works because a reaction with the hemoglobin in the blood causes the peroxide to oxidize the phenolphthalein not because of any reaction with amino acids. Edited January 20, 2009 by bob000555 Link to comment Share on other sites More sharing options...
UC Posted January 21, 2009 Share Posted January 21, 2009 (edited) Diliute solutions of silver nitrate (which are colorless) leave impressive purple stains wherever they touch skin, but I can't really recommend smearing them on yourself. Henna (lawsone) and the juice from black walnut fruits (juglone) are nice skin-reactive orangey-brown dyes that aren't toxic if you want temporary coloring. Edited January 21, 2009 by UC Link to comment Share on other sites More sharing options...
YT2095 Posted January 21, 2009 Share Posted January 21, 2009 the chem you`re after is likely to be ninhydrin. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now