Passive sampling and stir bar sorptive extraction for the determination of endocrine-disrupting compounds in water by GC-MS.

A new method using the extraction and preconcentration capabilities of stir bar sorptive extraction, combined with high-resolution gas chromatography and mass spectrometry, was developed for the determination of five selected endocrine-disrupting compounds (4-n-nonylphenol, bisphenol A, estrone, 17beta-estradiol, and 17alpha-ethinylestradiol) in water. In situ derivatization to transform the phenolic compounds into lipophilic and volatile analytes was carried out with acetic anhydride. Two different methods of headspace derivatization to further improve the chromatographic properties of 17beta-estradiol and 17alpha-ethinylestradiol were developed and compared. The optimized method provided good sensitivity (limits of quantitation 1.2-2.6 ng), repeatability (relative standard deviation 2-9%), and reproducibility (relative standard deviation 10-17%). Passive sampling by means of polar organic chemical integrative samplers was applied to monitor river waters used as supply sources for drinking water treatment plants in the Liguria region of Italy. The analytes showed a different distribution at the three sites considered; bisphenol A proved to be the most abundant, ranging from 185 to 459 ng per sampler.