Stir bar sorptive extraction and large volume injection gas chromatography to determine a group of endocrine...

Stir bar sorptive extraction (SBSE) combined with gas chromatography (GC) with mass spectrometric detection (MS) has been applied to determine a group of suspected endocrine disrupters in water samples. One centimeter stir bars coated with PDMS were used to extract the analytes and then solvent desorption was carried out. The absorption and desorption parameters in SBSE were optimized and large volume injection was used with a programmed temperature vaporizer injector (PTV) in GC to enhance the sensitivity of the method. The linear range of some endocrine disrupters was between 0.05 and 5 microg l(-1) and limits of detection were 0.01-0.24 microg l(-1) under full scan acquisition mode. The repeatability and reproducibility of the method (n = 5) for Ebro river water samples spiked at a level of 0.5 microg l(-1) was below 13 and 23%, respectively. Recoveries between 42 and 96% were obtained with the exception of atrazine. The method was applied to analyze real water samples from the Ebro River and irrigation streams of Ebro Delta and some of the compounds studied (aldrin, dieldrin, 4,4'-DDE and 4,4'-DDT) were found in some of them between detection and quantification limits.