what is a simple test to detect the presence of a carbonyl and to identify it?

A carbonyl is either a ketone or an aldehyde. In order to see whether the carbonyl group is present (C double bond O), 2,4-dinitrophenylhydrazine must be used. If an orange/yellow precipate is formed, then a carbonyl group is present. Then, you must purify the precipitate by recrystalisation and measure its melting point. then compare the melting point to known values to determine the compounds identity.