FIELD: analytical chemistry.
SUBSTANCE: in accordance to method, solution of maleinimide sample in concentrated acetic acid is subjected to nitration by mixture 1:1 of concentrated nitric acid and sulfuric acid during 10 minutes at room temperature, after that it is processed with 20-22% water solution of sodium hydroxide. Yellow-colored aciform salt is formed, solution is acidified with 0,7-1,0 ml 1,0 M of hydrochloric acid and 0,3-0,4 ml 0,6 M of water solution of chlorine iron (III) is added. Brightly red-colored solution is formed, which photo-metered at 315 nm relatively to water in 1 centimeter bath.
EFFECT: increased detection sensitivity.
2 tbl
