A sensitive electron-capture gas–liquid-chromatographic method for the determination of sub-nanogram quantities of prostaglandin F2α was developed. The method is based on the sub-microgram scale conversion of the prostaglandin into the electron-capturing pentafluorobenzyl ester, and analysis of the latter as the tris-trimethylsilyl ether. The lower limit of detection was 12.5pg of the ester injected ‘on-column’ as the silylated product. The method was successfully applied to the determination of prostaglandin F2α in monkey plasma. The specificity of the analytical procedure was increased by incorporating a thin-layer chromatographic fractionation before gas–liquid chromatography. The utility of the analytical methodology developed was demonstrated by its application to the determination of plasma concentrations of intact prostaglandin F2α in a Rhesus monkey, after subcutaneous administration of a single dose of prostaglandin F2α. The electron-capture gas–liquid-chromatographic assay is compared with the radioimmunoassay and the gas–liquid-chromatographic–mass-spectrometry assay for the determination of prostaglandin F2α.
