Selected reaction monitoring during gas chromatography/mass spectrometry of eicosanoids

Gas chromatography/electron capture negative ion mass spectrometry of eicosanoids, as pentafluorobenzyl (PFB) ester, methyl oxime (where applicable), trimethylsilyl (TMS) ether derivatives, is reported using a double‐focusing instrument of trisector configuration. Sub‐picogram detection limits were observed for prostaglandins E 1 , E 2 and F 2α during selected ion monitoring (SIM) of [M PFB] − ions. Selected reaction monitoring (SRM) of [M PFB] − → [M PFB TMSOH] − , occurring in the first field‐free region, was of modest sensitivity, reflecting the stability of the [M − PFB] − ions. The leukotriene B 4 (LTB 4 ) derivative was successfully analyzed by SIM at the low‐picogram level. In this instance, the fragmentation [M PFB] − →[M PFB TMSOH] occurred in high yield in the first field‐free region. The advantageous improvement in selectivity of detection that may be achieved with SRM was evident during the analysis of a serum extract for LTB 4 .