Evaluation of electrospray ionization and atmospheric pressure chemical ionization for simultaneous detection of estrone and its metabolites using high-performance liquid chromatography/tandem mass spectrometry.

The levels of estrogens and/or their metabolites play important roles in carcinogenesis, reproductive function, and sexual development during perinatal and adolescence periods. The main purpose of this report was to investigate the applicability of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with electrospray ionization (ESI) and/or atmospheric pressure chemical ionization (APCI) for simultaneous detection of estrone (E1) and its six metabolites. Both positive and negative ionization modes in ESI and APCI were used to evaluate the signal responses of seven target analytes. Among the seven target analytes, five analytes, E1, 16alpha-hydroxyestrone, 2-methoxyestrone, 4-methoxyestrone, and 2-hydroxyestrone-3-methyl, produced signals with the best signal-to-noise (S/N) ratios in positive APCI-MS/MS mode, while the other two analytes, 2-hydroxyestrone and 4-hydroxyestrone, yielded the best S/N ratios in negative ESI-MS/MS mode. Based on the results of the evaluation, HPLC-APCI-MS/MS with switching between positive and negative modes was recommended for simultaneous detection of E1 and its six metabolites. The proposed analytical scheme was successfully applied in the analysis of cell culture medium of Human liver carcinoma cells treated with varying amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin.