Compounds Matrix Extraction Clean-up Derivatization Separation and detection method MS system LOD (ng/l) Reference E2, E1, EE STP effluent SPE (C18 col)    -SPE (C18 col) -HPLC fraction. -LLE - GC-(EI)-MS Finnigan MAT Magnum ion trap 0.2 (17) E2, E1, EE STP effluents SPE (C18 col)    -HPLC fraction. - GC-MS Not reported 0.5-1 (111) E2, 17α-E2, E1, EE Surface and drinking water SPE (LiChrolut EN) PFBCI GC-(NCI)-MS HP 5973 MSD (Hewlett- Packard) 0.05-0.15 (112) E2, E1, EE STP effluent SPE (ENV+ col) -LLE, GCP (Biobeds SX- 3) -hydrolysis Acetic anhydride GC-(EI)-MS Not reported Not reported (59) E2, E1, EE, 17α-E2 (SS) River water and STP effluent Contineous LLE - Bis- (trimethylsilyl)triflouro- acetamide with 10% trimethylchlorosilane   GC-(EI)MS HP 5970 MSD (Hewlett- Packard) 58 (only E2) (53) E2, E3, E1, EE STP effluent SPE (LiChrolut EN/Bondesil C18 col.) Silicagel 60 MSTFA/TMSI/DTE (1000:4:2) GC-(EI)MS HP 5970B MSD (Hewlett- Packard) 1 (58) EE STP effluent SPE (Empore C18 disk) - - GC-(EI)MS Finigan Voyager 74 (113) E2, EE Surface water     SPE (C18 col. Or disk or PS- DVB col.) or - MTBSTFA GC-(EI)MS Voyager (Interscience) 50-300 (55)