Resolution of prostaglandin p-nitrophenacyl esters by liquid chromatography and conditions for rapid, quantitiative p-nitrophenacylation.

The p-nitrophenacyl esters of a number of closely related and isomeric prostaglandins were resolved by HPLC on a microparticulate silica gel column (Zorbax-Sil, DuPont). Ten F-series prostaglandin analogs, eight E-series prostaglandin analogs, the isomeric 15(R)- and 15(S)-methyl prostaglandins of the E- and F-series and, lastly, PGA2 and PGB2 were chromatographed under conditions generating 2,000 to 7,000 theoretical plates. Conditions are described for quantitative conversion of prostaglandins to p-nitrophenacyl esters in less than 6 minutes at room temperature. Linear peak height and peak area plots were obtained for in-situ esterified PGE2 p-nitrophenacyl ester over the range of 0.4 - 3.1 mug. The lower limit of detection of this ester is about 1 ng. A linear relationship is observed between silica gel TLC 1/Rf values and HPLC retention times as predicted by theory.