Determination of endocrine disrupting compounds in marine water by nanoliquid chromatography/direct-electron ionization mass spectrometry

We present a new method for the determination of 29 endocrine-disrupting compounds in marine water. This method is based on a solid-phase extraction preconcentration technique, followed by a nanoscale liquid chromatography/direct-electron ionization (EI) mass spectrometric analysis. Direct-EI is a novel technique for the rapid conversion of a GC/MS into an efficient and reliable LC/MS for EI detection. The capability to acquire EI mass spectra of the analytes, and to operate in selected ion monitoring mode during real sample analyses, allows certain identification and precise quantification. In addition, this method is not influenced by the polarity of the analytes and does not require different detection modes (positive and negative) for identification with API techniques. Limits of detection of the method span from 0.4 to 118.7 ng(.)L(-1), corresponding to an instrumental detection limit of 0.005-1.260 ng. Linear regression and recovery experiment data, together with their standard deviations, are also presented. Marine water samples were collected along the middle-western Adriatic Coast (Italy), near the shore and at the mouth of rivers and canals.