Application of stir bar sorptive extraction in combination with column liquid chromatography for the determination of polycyclic aromatic hydrocarbons in water samples

The new technique of stir bar sorptive extraction (SBSE) using stirrers 10mm long coated with 55µl polydimethylsiloxane (PDMS) was used to determine polycyclic aromatic hydrocarbons (PAHs) from water samples. The desorption of the extracted analytes was performed with ultrasonic treatment in autosampler vials with glass flat bottom inserts using 150µl of acetonitrile (ACN) or an ACN-water mixture (4:1) as solvent. The PAHs were determined with column liquid chromatography (LC) and fluorescence detection. The recoveries of the stir bar sorptive extraction for the compounds investigated were between 58% and about 100%, and the detection limits of this method under the given conditions (extraction from a 10ml sample, 1h extraction time and 10min desorption time) were very low (between 0.2 and 2ng/l). The standard deviations (n=5) using five different stirrers at a concentration level of 50ng/l ranged between 4.7 and 13.5%.