Stir bar sorptive extraction (SBSE), a novel extraction technique for aqueous samples: Theory and principles

The theory and practice of a novel approach for sample enrichment, namely t he application of stir bars coated with the sorbent polydimethylsiloxane (P DMS) and referred to as stir bar sorptive extraction (SBSE) are presented. Stir bars with a length of 10 and 40 mm coated with 55 and 219 mu L Of PDMS liquid phase, respectively were applied. The 10-mm stir bars are best suit ed for stirring sample volumes from 10 up to 50 mL, whereas 40-mm stir bars are more ideal for sample volumes up to 250 mL. Depending on sample volume and the stirring speed, typical stirring times for equilibration are betwe en 30 and 60 min. The performance of SBSE is illustrated with the analysis of volatile and semivolatile micropollutants from aqueous samples. Detectio n limits using mass selective detection are in the low ng/L range for a wid e selection of analytes from the EPA priority pollutant lists including ana lytes ranging in volatility from 1,1,1-trichloroethane to chrysene. For the extraction of selected compounds from 200-mL, samples, detection limits be low 0.1 ng/L are reached in the selected ion monitoring mode. A comparison between SBSE and solid-phase microextraction is made. (C) 1999 John Wiley & Sons, Inc.