Orthgiess, Erhard published the artcileColorimetric determination of anionic surfactants, Application of Dimidium bromide, the publication is Tenside, Surfactants, Detergents (1990), 27(4), 226-8, database is CAplus.
A method for the determination of anionic surfactants such as alkyl- and alkylarylsulfates, -sulfonates, and -sulfosuccinates in aqueous solutions is based on the absorbance measurement of surfactant-dye (i.e., 3,8-diamino-5-methyl-6-phenylphenanthridinium bromide) complexes at 525 nm. The technique is simpler and faster than other colorimetric methods and can be used for the anal. of 1 × 10-4 to 5 × 10-7 M solutions
Tenside, Surfactants, Detergents published new progress about 518-67-2. 518-67-2 belongs to bromides-buliding-blocks, auxiliary class Other Aromatic Heterocyclic,Salt,Amine,Benzene, name is Dimidium bromide, and the molecular formula is C20H18BrN3, Application of Dimidium bromide.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary