Determination of polynuclear aromatic hydro-carbons and mononitrated derivatives in air and diesel particulates

A method is described for the determination of three- to six-ring polynuclear aromatic hydro-carbons (PAHs) and mononitrated PAHs (nitro-PAHs) in particulate matter. The procedure includes Soxhlet extraction followed by fractionation using gel filtration chromatography and normal-phase liquid chromatography with an aminosilane stationary phase. The resulting fractions were separated by capillary gas chromatography (GC) into individual PAHs and nitro-PAHs which were detected by a flame-ionization detector and a thermal energy analyzer, respectively. Commercially available standards were used for quantification. Individual peak assignments were confirmed by using both mass spectral and retention index data obtained through computerized capillary GC-mass spectrometry. Several samples were processed, including a certified diesel particulate reference material supplied by the National Bureau of Standards for the purpose of evaluating analytical methods. This method may also be applicable in the determination of certain carbonyl PAHs.