Analytical method development of long-chain ketones in PM2.5 aerosols using accelerated solvent extraction and GC/FID/MSD

An analytical method has been developed to determine long-chain n -alkan-2-ones (C-10-C-33 ) in atmospheric particulate matter. This involves (1) solvent extraction with a Dionex Accelerated Solvent Extractor (ASE 200), followed by nitrogen blowdown; (2) a clean-up procedure using silica-gel chromatography to separate fractions of different polarities; and (3) gas chromatography with mass-selective detector (GC/MSD) identification and gas chromatography with flame ionization detector (GC/FID) quantitation. The recovery rates in the extraction/blowdown steps were quantified at different extraction and blowdown temperatures. The maximum recoveries for the selected ketones, obtained at 40degreesC for both extraction and blowdown, are 70-100% for the extraction step and 92-101% for the combined steps of blowdown and silica gel separation depending on the chain length of the ketones. The overall analytical instrumental detection limits for the ketones are <0.24 ng/muL in the GC/FID.