Determination of four quinones in diesel exhaust particles, SRM 1649a, an atmospheric PM2.5

Quinones are reactive organic compounds and are known to initiate reactions associated with many toxicological events. Their presence in air pollution has been demonstrated, but routine quantitative measurements are lacking. A quantitative method for the determination of four quinones was developed using diesel exhaust particles (DEP) and National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1649a. The method was then used to analyze ambient air samples from different sites in Southern California. After extraction in dichloromethane, the target compounds were converted to their stable diacetyl derivatives and determined by electron impact GCMS using selected ion monitoring. Calibration plots were obtained with deuterium-labeled internal standards. The four quinones, 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), 9,10-phenanthraquinone (9,10-PQ), and 9,10-anthraquinone (9,10-AQ), were quantified in DEP, in SRM 1649a, and in ambient air samples of PM2.5 collected in several rural and urban sampling locations upwind and downwind of major emission sources in Central Los Angeles. Mean concentration of individual target quinones ranged from 7.9-40.4 mug/g in the DEP, and from 5-730 pg/m(3) in the PM2.5 samples. Precision (repeatability and reproducibility) varied from 2-22%. Further measurements of these species in future air samples should be considered in light of their potential health significance.