Active sampling followed by solid-phase microextraction for the determination of pyrethroids in indoor air

A method based on solid-phase enrichment followed by headspace (HS) solid-phase microextraction (SPME) is optimized to determine pyrethroids in air. By active sampling, pyrethroids present in air are retained in 25 mg of activated florisil and then transferred from the solid sorbent to an SPME fiber in the HS mode. A small volume of solvent is added to the adsorbent to favor this process. The selection of the adsorbent, as well as the optimization of certain parameters affecting the SPME, is performed using an experimental design strategy. Linearity is studied by external calibration in a wide range of concentrations using gas chromatography coupled to three different detection systems: electron capture detection, micro-electron capture detection, and mass spectrometry. An analysis of variance with a lack-of-fit test is run to validate the calibration data. Breakthrough of the adsorbent was studied sampling from 0.5 to 10 m3 air, demonstrating that 1 m3 air could be sampled without losses of pyrethroids. Quantitative recoveries are obtained at three concentration levels, with adequate repeatability. Limits of detection of the method are estimated at the sub-ng/m3 level in most cases, well below the regulatory limits. Finally, several real indoor samples are collected and analyzed by the proposed method. Identification and quantitation of all target analytes present in the room air are possible.