title: [Simultaneous determination of nine estrogens in eel by ultrafast liquid chromatography-tandem mass spectrometry with isotope dilution technique and solid-phase extraction].
abstract: OBJECTIVE
  Developing a rapid and sensitive analytical method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) with solid-phase extraction (SPE) for the simultaneous determination of nine estrogens (dienestrol, diethylstilbestrol, estrone, hexestrol, 17-alpha-estradiol, 17-beta-estradiol, estriol, 17alpha-ethinylestradiol and estradiol valerate) in eel.
  
  
  METHODS
  After the sample was extracted by acetonitrile and cleaned by Waters Oasis HLB solid-phase extraction cartridge, the UFLC separation was performed on a Shim-pack XR-ODS II column (100 mm x 2.0 mm, 2.2 microm) with a linear gradient elution program of methanol solution containing 0.04% ammonia (v/v) and 0.04% ammonia aqueous solution (v/v) as the mobile phase. Electrospray ionization was applied and operated in the negative multiple reaction monitoring (MRM) mode. The quantitation was used by isotope internal standard dilution technique.
  
  
  RESULTS
  The results showed that the limits of quantitation (LOQs, S/N(10) were in the range of 0.07-0.4 microg/kg, the calibration curves were in good linearities for the nine analytes in the range of 0.5-50.0 microg/L with the correlative coefficients (r2) more than 0.998, the recoveries were between 81.0% and 110.0% with the relative standard deviations (RSDs) of 1.92%-8.24%. Additional, the mass spectra characterization of the nine estrogens was discussed and the fragmentation pathways were speculated.
  
  
  CONCLUSIONS
  The developed method is rapid, sensitive, specific and reproducible, and adapts not only to the simultaneous determination of the nine trace estrogens including the epimer of 17-alpha-estradiol and 17-beta-estradiol but also to the identified detection in other fish tissues.
authors: Ningbo Municipal Center for Disease Control and Prevention, Ningbo Key Laboratory of Poison Research and Control, Ningbo 315010, China. chenxhnb@163.com
authors: Xiaohong
authors: X
authors: Chen
authors: Shanshan
authors: S
authors: Yao
authors: Xiaoping
authors: X
authors: Li
authors: Yonggang
authors: Y
authors: Zhao
authors: Micong
authors: M
authors: Jin
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D004028:Dienestrol / Q000032:analysis; D004054:Diethylstilbestrol / Q000032:analysis; D004524:Eels; D004967:Estrogens / Q000032:analysis*; D004970:Estrone / Q000032:analysis; D005396:Fish Products / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D011865:Radioisotope Dilution Technique; D052616:Solid Phase Extraction / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004967:Estrogens; D004970:Estrone; D004054:Diethylstilbestrol; D004028:Dienestrol