A nuclear magnetic resonance method for the determination of the purity of commercial dequalinium chloride.

4-amino-1-(10-4'-quinaldinylaminodecyl)quinaldinium chloride (3) has been identified through nuclear magnetic resonance (NMR) studies as one of the impurities of a commercial sample of dequalinium chloride (CAS 522-51-0). The NMR technique is proposed as a rapid method for the recognition and quantification of the impurities in dequalinium chloride samples.