The project is to develop a method of the analysis of polycyclic aromatic hydrocarbons (PAHs) and nitrated-polycyclic aromatic hydrocarbons (N-PAHs) in diesel engine emission and ambient air particles and gas phase. Data obtained will be used for the assessment of human health and environmental impact. The principle of the method is to extract NPAHs by Soxhlet apparatus for a period of 16 to 20 hours with DCM. Prior to extraction samples are spiked with a solution containing isotopically-labelled NPAHs. The extract is dried over anhydrous sodium sulphate, filtered through filters and blown down to dryness. Samples are redissolved in dimethyl sulfoxide (DMSO) and aliphatic compounds are removed from the solution by liquid-liquid extraction with hexane.The DMSO solution is diluted with water and aromatic fraction is extracted from DMSO/water with cyclohexane. The cyclohexane fraction is concentrated and is subjected to the HPLC normal-phase fractionation on an analytical silica column with a gradient of DCM in hexane as a mobile phase. The N-PAH fraction is collected and concentrated to a known small volume for analysis. All procedures are performed under subdued yellow light and samples are placed in amber glassware or wrapped in foil as NPAH are light sensitive. Qualitative/quantitative analysis for N-PAHs is performed with a high-resolution gas chromatograph-electron capture detector or mass spectrometer (HRGC-ECD or MS). Quantification is based on the use of surrogates (isotopically-labelled compounds added before sample workup) as internal standards. An isotopically-labelled standards, added to sample extracts immediately before analysis, serve as recovery standards for the quantification of surrogate recovery. The developed method was applied to the analysis of diesel engine emission particulate matter and ambient air particle/gas phase samples.

Polycyclic aromatic hydrocarbons、nitrated Polycyclic aromatic hydrocarbons、auto emission