Qulitative Test for AA and Proteins

For: Free amino acids

Reagent: ninhydrin

Result: violet

Ninhydrin

For: Peptide bonds

Reagent: Cupric sulfate

Result: violet

Biuret

For: Aromatics

Reagent: Nitric acid

Result: Yellow

Xanthoproteic

For: Phenolic compounds

Reagent: Mercury in nitric acid

Result: rose/salmon

Millons

For: Indole

Reagent: Glucoxylic acid

Result: Violet ring

Hopkins Cole

For: guanedine group

Reagent: alpha napthol

Result: reddish white

Sakaguchi

For: thiol group

Reagent: sodium nitroprusside

Result: red

Nitroprusside

For: S containing compound

Reagent: lead II acetate

Result: black or brown ppt

Fohls

For: tyr, his

Reagent: diazotized sulfanilic acid

Result: red

Paulys

Rx: ninhydrin

Ninhydrin

Rx cupric sulfate

Biuret

Rx nitric acid

Xanthoproteic

Mercury in nitric acid

Millons

Rx glycoxylic acid

Hopkins cole

Rx alpha napthole

Sakaguchi

Rx sodium nitroprusside

Nitroprusside

Rx lead II acetate

Fohls

Rx diazolized sulfanilic acid

Paulys

for free amino acids

Ninhydrin

For peptide bonds

Biurets

For aromatic

Xanthoproteic

For phenolic compounds

Millons

For indole

Hopkins cole

For guanedine

Sakaguchi

For thiol group

Nitroprusside

For s containing compounds

Fohls

For tyr, his

Paulys