Automated stir plate (bar) sorptive extraction coupled to high-performance liquid chromatography for the determination of polycyclic aromatic hydrocarbons

Automated methods of PDMS/beta-CD/divinylbenzene-coated stir plate sorptive extraction (SPSE) coupled to HPLC-fluorescence detector were reported for the first time. Three automation modes, static SPSE, circular flow SPSE and continuous flow SPSE, were evaluated and critically compared with stir bar sorptive extraction by using six polycyclic aromatic hydrocarbons as model analytes. It was found that the operable sample volume for circular flow SPSE and continuous flow SPSE was larger than that for static SPSE. Under the same extraction conditions, continuous flow SPSE exhibited the highest extraction efficiencies in all automated modes and manual stir bar sorptive extraction for the target compounds. Compared with the manual operation (approximately 5-10 mm), automated SPSE required a relatively short time (117-180 s) to finish sampling, washing and sample loading. Besides being labor-saving and time-saving, automated SPSE has other advantages, such as no time limit and non-attended operation. The proposed continuous flow PDMS/beta-CD/divinylbenzene-coated SPSE-HPLC-fluorescence detector was successfully applied to environmental water analysis.