A facde means of optumzmg solvent composltlons and reagent concentrations for the peroxyoxalate chemdununescence (PO-CL) detectlon of fluorescent compounds urlth bdem~2_(3.6,9-tnoxadecyl~henyll oxalate (TDPO) and hydrogen pemde m hqmd chromatography (LC) was developed The reation tune course of CL was easdy obtamed by changmg the PTFE tube lengths m the nuxmg devux m the L.C flow system m which the column effluent and CL reagent solution flow The addtbon of a phthalate ester to the basx solvent nuxture for the chenulummogemc reagents, ethyl acetate-acetomtnle (50 + SO, v/v) contammg TDPO and hydrogen pexxode, resulted m a consIderable redu&on m the baselme noise level wthout decreasmg the signal of a fluorescent compound, dtpyndamole Phthalate esters havmg branched-cham moleties were more effectwe, dl-2-ethylhexyl phthalate (DOP) bemg the best m reducmg the baselme noise A muture of 0 25 mM TDPO and 25 mM hydrogen peromde m ethyl acetate-acetomtie-DOP (50 + 49 75 + 0 25, v/v/v) (13 ml mm-') as a chenulummogemc reagent solution for the eluent [acetomtrde-50 mM umdazole mtrate buffer (pH 6 0) (45 + 55, v/v) (10 ml mm-')] was optmmm for the detectlon of am01 levels of fluorescent compounds The detectlon lmut for drpyndamole was 10 am01 (srgnal-to-now ratlo = 2) Under the same condluons, the detection bmtt for dansylated phenylalanme was 800 am01