Dynamic sonication-assisted solvent extraction of organophosphate esters in air samples

A new system for extracting solid samples based on dynamic sonication-assisted solvent extraction (DSASE) is described. The technique is highly efficient with respect to both time and solvent consumption. In tests reported here, organophosphate esters were extracted from air sampling filters in 3 min with an extraction volume of 600 μL of solvent. Furthermore, it was possible to replace a previously used chlorinated solvent with a halogen-free solvent mixture. The sample was placed in a cartridge through which fresh solvent was pumped continuously. A restrictor connected to the outlet of the cartridge allowed the system to be used at a temperature of 70 °C without reaching the boiling point of the solvent. Both spiked and non-spiked native samples were used for the evaluation, which clearly revealed a stronger analyte–matrix interaction in native samples. The DSASE technique was shown to recover larger amounts of organophosphate esters from native samples, compared to a static method. DSASE was applied to air samples collected in a lecture hall and from above a computer monitor.