Direct analysis of the major human seminal prostaglandins by thermospray high-performance liquid chromatography-mass spectrometry.

Thermospray high-performance liquid chromatography-mass spectrometry (HPLC-MS) can be a powerful tool for characterizing eicosanoids in complex biological samples. The positive ion spectra obtained from primary prostaglandins such as PGE1 PGE2, 19-OHPGE1, 19-OHPGE2, PGF2 alpha, PGD2, 6-keto-PGF1 alpha and from leukotriene B4 are very simple, with base peaks corresponding to ions arising from the loss of H2O from the (M + H)+ and (M + NH4)+ ions, except for PGB2 and PGF2, where the latter two ions predominate. The application of this technique to the concurrent determination of the E1 and E2 prostaglandins and their 19-hydroxylated derivatives in human semen is described. The technique affords a moderate level of sensitivity (5-20 ng on-column) and excellent specificity so that virtually no sample manipulation is required other than dilution in acetone and centrifugation. The clear supernatant is injected directly into the HPLC-MS system. A similar analysis by either gas chromatography (GC) or GC-MS would need multi-step derivatization, thus increasing the sample manipulation required and the total analysis time.