Determination of nitrated polycyclic hydrocarbons in aerosols using capillary gas chromatography combined with different electron capture detection methods

A method is described which allows the determination of subnanogram concentrations of mono- and dinitrated polyaromatic hydrocarbons with two to four ring systems in aerosol samples. High performance liquid chromatography is used to separate the nitro compounds from other classes of substances. Carbozoles elute in the same fraction. Both electron capture detection and negative ion chemical ionization mass spectrometry combined with capillary gas chromatography are used for quantification. Use of these two methods leads to a considerable improvement of selectivity and sensitivity for nitrated compounds. In contrast to the situation with a nitrogen-sensitive detector, carbazoles do not interfere and detection limits in the order of 10–200 pg/m³ are possible. The applicability of the method is critically discussed. Determination of nitrated polyaromatic hydrocarbons in aerosol samples from an aluminum smelter serves as an example.