Separation of large polycyclic aromatic hydrocarbons in particulate matter by liquid chromatography

The level of mutagenic activity of particulate polycyclic aromatic hydrocarbons (PAHs) is highly dependent upon structure, so that similar isomers can range from being very active to totally inactive. The suitability of GC/MS or LC with single wavelength absorbance or fluorescence monitoring, coupled with the availability of standards, has resulted in emphasis being placed on the small PAHs (five or fewer rings).In the work reported here, LC was coupled to a computerized photodiode array detector. The former separated the components in a diesel particulate matter extract and the latter spectrally differentiated the large PAHs (more than 24 ring-carbons). Since each PAH has a characteristic UV/VIS absorbance spectrum, each generated a unique pattern of absorbance maxima and minima. Computerized pattern recognition techniques were then used to investigate quantitative structure-activity relationships of the PAHs as predictors of carcinogenicity.The chemical profile of a series of unsubstituted PAHs, for which carcinogenic data was available, was represented by 17 descriptors of the reactivity and properties of those PAHs. Using this data set, the properties of another series of PAHs were found to be consistent with their reported carcinogenicity.