CHARACTERIZATION OF NITROGEN-CONTAINING AROMATIC-COMPOUNDS IN SOIL AND SEDIMENT BY CAPILLARY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY AFTER FRACTIONATION

Nitrogen-containing aromatic compounds (NCACs) are characterized in soil and sediment by full-scan capillary gas chromatography-mass spectrometry under electron ionization. The approach makes use of fractionation of methylene chloride extracts based first on partitioning of the basic compounds into acid. The neutral NCACs are then isolated by preparative thin-layer chromatography which serves to separate them from the bulk of the polynuclear aromatic hydrocarbons. NCACs can then be determined using deuterated internal standards to 100-mu-g/kg or below. Examples of determinations in sediment and creosote-contaminated soil are given. An advantage of the two-step fractionation scheme is the chemical separation of azaarenes and cyanoazaarenes of the same elemental composition which facilitates identification of compound class and simplifies chromatographic separations.