1 ET Ethidium 1.000 2 PZ5 5-hept-6-ynyl-6-phenyl-phenanthridin-5-ium-3,8-diamine 0.828 3 PRM 3,8-diamino-5[3-(diethylmethylammonio)propyl]-6-phenylphenanthridinium 0.774 4 LG1 3,11-difluoro-6,8,13-trimethyl-8h-quino[4,3,2-kl]acridin-13-ium 0.724