A simple and sensitive method for measuring quinoid polycyclic aromatic hydrocarbons (PAHQs) in soluble organic fraction (SOF) of airborne particles based on two-dimensional high-performance liquid chromatography (HPLC) with fluorescence detection was established. The system involves a reversed phase column with naphtylethyl groups bonded silica packing material for sample clean-up, a 6-port switching valve, an ODS column for trapping the fraction containing PAHQs, a reversed phase column with cholesteryl groups bonded silica packing material for sample separation, and a Pt-Rh catalytic column for the reduction of PAHQs to a corresponding fluorescent compound. The accuracy of the assay, as applied to airborne particulate sample extracts spiked with known amounts of PAHQs were 91 – 107%. The detection limits were 19 to 2000 fmol per injection (signal-to-noise ratio = 3), and the calibration range was from 1 to 100 pmol with excellent proportionality (R2≥0.9992) for four kinds of PAHQs: benz[a]anthracene-7,12-dione, fluoranthene-2,3-dione, pyrene-1,6-dione, and pyrene-1,8-dione. PAHQs in SOF of airborne particles collected in Kyoto, Japan were successfully measured using the established analytical method with simple sample-preparation steps: ultrasonic extraction in organic solvent and concentration under reduced pressure and/or a nitrogen stream.
