Resolution of mixtures of steroidal hormones with micellar eluents of sodium dodecyl sulphate and acetonitrile or pentanol

An optimization strategy was applied to explore the capability of hybrid mi cellar eluents of sodium dodecyl sulphate (SDS), using acetonitrile or pent anol as modifiers, to resolve mixtures of eleven steroids showing a wide ra nge of hydrophobicity (clostebol acetate, dehydrotestosterone, dydrogestero ne, medroxyprogesterone, medroxyprogesterone acetate, methandienone, methyl testosterone, progesterone, testosterone, testosterone enanthate and testos terone propionate). The accurate prediction of the retention behaviour of t he steroids, with relative errors in the 0.8 - 1.7% and 0.4 - 2.9% ranges f or SDS-acetonitrile and SDS-pentanol eluents, respectively, demonstrated th e reliability of the methodology. Acetonitrile and pentanol had a complemen tary effect in these analyses. The elution strength of acetonitrile was wea ker, but allowed higher efficiencies. A 0.094 M SDS-16% acetonitrile eluent separated seven steroids (dehydrotestosterone, dydrogesterone, medroxyprog esterone, medroxyprogesterone acetate, methandienone, methyltestosterone an d testosterone) in 27 min, while the most hydrophobic steroids were strongl y retained. In contrast, a 0.125 M SDS-5.8% pentanol eluent permitted the e lution of a mixture of eight steroids dehydrotestosterone, dydrogesterone, medroxyprogesterone acetate, methandienone methyltestosterone, progesterone , testosterone enanthate and testosterone propionate) of diverse hydrophobi city in 14 min. With this eluent, however, the peaks of dehydrotestosterone -medroxyprogesterone and methandienone-testosterone were highly overlapping .