3,3-Dichlorophenylsulfonphthalein; CPR; Chlorophenol red (0.1% in ca. 20% in ethanol); dichlorophenolsulphonephthalein; alpha-(3-chloro-4-hydroxyphenyl)-alpha-(3-chloro-4-oxocyclohexa-2,5-dienylidene)toluene-2-sulphonicacid; Chlorophenol red (0.04 in water); 4,4'-(1,1-dioxido-3H-2,1-benzoxathiole-3,3-diyl)bis(2-chlorophenol); 2-chlorophenol,1,1-dimethyl-3-phenyl-urea