Development of a database strategy based on liquid chromatography-quadrupole time-of-flight mass spectrometry for the screening of 75 estrogenic chemicals from treated sewage effluent

The detection of endocrine disrupting chemicals such as estrogenic compounds in environmental samples is a hot topic of research. In this context, this study describes a new screening method for 75 estrogenic chemicals from environmental water samples based on two databases built from the data obtained from liquid chromatography with quadrupole time-of-flight mass spectrometry. A first database, named "DATABASE I," is constructed from the retention time and m/z of molecular weight-related ions with measured accurate mass of the 75 estrogenic chemicals. A second database, "DATABASE II," includes the collision-induced fragmentation spectra with measured accurate mass of the compounds. These databases are respectively applied for a rough screening and precise identification of the estrogenic chemicals of sewage effluents as follows: Step (1): A treated sewage effluent sample is subjected to analysis using the time-of-flight scan mode, and a rough screening using DATABASE I is performed. Step (2): The obtained candidate estrogenic chemicals by step 1 are measured using the targeted tandem mass spectrometry mode in which collision energy dependence fragmentations of them are induced. The resulting fragmentation mass spectra are screened using DATABASE II. The application of these two databases improved the accuracy in the identification of estrogenic chemicals, reducing the risk of misidentification.