1. Traces of acetone may be detected in ethanol or water or in methylethyl ketone by means of diazotized aniline, 10−3% of acetoacetic ester can be detected in ethyl acetate by means of diazotizedp-phenetidine, 10−5% acetylacetone in aldehyde, acetylphenylhydrazine in the presence of acetanilide,m- oro- in the presence ofp-nitraniline.