Analysis of estrogenic compounds in environmental and biological samples by liquid chromatography–tandem mass spectrometry with stable isotope-coded ionization-enhancing reagent

A sensitive and reliable stable isotope labeling technology was developed for the determination of estrogenic compounds in environmental and biological samples based on the derivatization of estrogenic compounds with 10-methyl-acridone-2-sulfonyl chloride (d0-MASC) and its deuterated counterpart d3-MASC. The labeling reaction of MASC with estrogenic compounds is simple and robust and can be carried out under mild conditions within 5 min. Internal standard-based quantification was achieved by this labeling strategy without the need of using expensive internal standard analogy to every analyte of interest. Meanwhile, the sensitivity obtained by liquid chromatography–tandem mass spectrometry (LC–MS/MS) was enhanced by 2–3 orders of magnitude compared to the underivatized counterparts. Application of the stable isotope labeling technology in relative and absolute quantification of estrogenic compounds in complicated samples indicated that the labeling strategy was effective in overcoming matrix effects. The proposed method was successfully applied to the analysis estrogenic compounds in different environmental and biological samples with high sensitivity and accuracy.