Separation of amino- and acetylamino-polycyclic aromatic hydrocarbons by reversed- and normal-phase high-performance...

In the field of chemical carcinogenesis, amino- and acetylamino-polycyclic aromatic hydrocarbons (PAHs) are among the most studied compounds. Many of these compounds have recently been detected in the environment. Presently, knowledge permitting predictions of the high-performance liquid chromatographic (HPLC) retention order of amino- and acetylamino-PAHs, particularly among their geometric isomers is lacking. In order to obtain a better understanding of the separation of these types of compounds, we have studied the separation of a series of structurally related amino- and acetylamino-PAHs derived from naphthalene, phenanthrene, anthracene, pyrene, benz[a]anthracene, benzo[a]pyrene, and benzo[e]pyrene by using reversed-phase and normal-phase HPLC columns of different types (monomeric, polymeric, and chiral stationary phase). The results indicate: (i) Pirkle-type chiral stationary phase columns and the Zorbax SIL column can efficiently separate both the amino-PAHs and acetylamino-PAHs; (ii) in general, there was no correlation between retention time and molecular size; (iii) when acetylamino-PAHs were separated on the monomeric Zorbax ODS column, the isomer with the acetylamino group located at the carbon position of higher electron density has a shorter retention time; and (iv) separation of the parent PAHs was better than that of the amino-PAHs and acetylamino-PAHs. Our results thus may provide useful information for the analysis of amino-PAHs, particularly for distinguishing the geometric isomers of environmental samples.