Analysis of six phenolic environmental estrogens in bullfrog blood by using dispersive solid-phase extraction and ultrafast liquid chromatography-tandem mass spectrometry

Abstract

A rapid, sensitive and accurate method for the simultaneous determination of six phenolic environmental estrogens, i. e., bisphenol A (BPA), diethylstilbestrol (DES), dienestrol( DE), hexestrol (HEX), 4-( tert-octyl)-phenol (4-tOP) and 4-nonylphenol (4-NP) in bullfrog blood by dispersive solid-phase extraction-ultrafast liquid chromatography-tandem mass spectrometry (dSPE-UFLC-MS/MS) was established. After protein precipitation, bullfrog blood samples were cleaned-up by dSPE method with ethylenediamine-functionalized Fe3O4, magnetic polymers (EDA-MPs) as adsorbent. The effects of precipitation solvents, adsorption time and the amount of EDA-MPs used on the recoveries of six phenolic environmental estrogens were investigated in detail. Chromatographic separation was performed on a Shim-pack XR-ODS II analytical column (100 mm x 2.0 mm, 2.2 microm). The mass spectrometer was operated by using electrospray ion (ESI) source in the multiple reaction monitoring (MRM) mode. The results showed that the linearities were in the range of 0.5-100.0 microg/L with correlation coefficients (r2) not less than 0.999 6 for all the six phenolic environmental estrogens. The lim- its of quantification (LOQs) (S/N > 10) in bullfrog blood samples were between 0. 075 microg/L and 0.40 microg/L. The recoveries were between 95.0% and 110.0% at three spiked levels. The precision values expressed as relative standard deviations (RSDs) were in the range of 0.6%-6.3%. The developed method can be applied to the routine analysis of the six phenolic environmental estrogens in bullfrog blood samples.