FIELD: analytical methods.
SUBSTANCE: naphtholmonosulfonic acids, in particular 1-naphtol-4 sulfonic acid and 1-naphtol-5-sulfonic acid, are isolated from treated waste waters from azo dye production. Isolation and concentration of acids is achieved by preliminarily adding N-cetylpyridinium chloride solution to aqueous solution of acids to obtain solution with concentration 1.2·10-4 M, after which hydrochloric acid solution is added to 1.0-0.1 M (pH 1-9). Extraction is effected with binary solvent mixture of acetone (41.0-41.5%) and diacetone alcohol (59.0-58.5%), whereas volume ratio of binary mixture to sample is 1:10. Ammonium sulfate is then used as salting-out agent.
EFFECT: achieved degree of isolation of naphtholmonosulfonic acids 98% and increased concentration factor to 17.
2 tbl, 27 ex
