Zone for warning of false results in oxidn. detection - contg. bis(hydroxyphenyl)azine and opt. also reducing agent

摘要

Warning of false results in oxidn. detection on absorbent carriers is achieved by having next to the detection zone a warning zone contg. one more more azines of formula (I) and opt. also a reducing agent. R = H, 1-12C alkyl or opt. substd. aryl; and R1 and R2 = H or 1-6C alkyl or alkoxy. USE/ADVANTAGE - Warning of false colour changes in indicator rods is simply obtd. using azines (I) which can be of the type previously used as per DE2107879 for free Cl2 detection. (I) is suitably 4-hydroxy-benzaldazine or vanillinazine and the reducing agent is, e.g. ascorbic acid or Ca sulphite.