a disinfecting concentrate includes a mixture of n - alkylated benzalkonium halides , preferably , n - alkylated benzyl ammonium chlorides or benzalkonium chlorides , each having from 8 to 18 carbon atoms in their respective alkyl portions , preferably 12 to 18 carbon atoms , and mixtures thereof . the concentrate further includes a preservative and water . use solutions prepared from the concentrate contain minor amounts thereof in order to be efficacious .