Abstract
1. The qualitative separation and quantitative estimation of the two isomeric azo compounds 2‐ and 4‐arylazo‐1‐naphthol‐3‐sulphonic acid by paper chromatography is described (aryl = 4′‐chloro‐, 2′‐nitro‐, 3′‐nitro‐, 4′‐nitro‐ and 2′,4′‐dinitro‐phenyl).