Simultaneous determination of five estrogens in eel blood by liquid chromatography-tandem mass spectrometry

Objective:To establish a method for the simultaneous determination of five estrogens residues,such as diethystilbestrol,estrone,17-alpha-estradiol,17-beta-estradiol and estriol in eel blood by liquid chromatography coupled with tandem mass spectrometry(HPLC-MS/MS).Methods: The blood was extracted by methanol acidified with 0.1% formic acid,cleaned and enriched by a Waters Oasis HLB solid-phase extraction(SPE) cartridge,the separation was performed on a XBridgeTM C18(150 mm×2.1 mm,5 μm) column by the mobile phase of acetonitrile and water both containing 0.08% ammonia(V/V) as a gradient eluent.Detection was carried out by HPLC-MS/MS using a negative electrospray ionization interface in the multi-reaction monitoring(MRM) mode.Results: Calibration curves were linear within the range of 0.1 μg/L～50.0 μg/L with the correlation coefficients more than 0.999,and the limits of quantification(LOQs)were between 0.1 μg/L～0.3 μg/L.The extraction recoveries were between 85.4%～113.0%,and the RSDs were between 2.0%～6.8%.Conclusion: The developed method is simple,accurate and high specific for the satisfactory determination of trace estrogens residues in eel blood.