SIMULTANEOUS IDENTIFICATION OF DIFFERENT CLASSES OF HYDROCARBONS AND DETERMINATION OF NITRO-POLYCYCLIC AROMATIC-HYDROCARBONS BY MEANS OF PARTICLE-BEAM LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

LC-MS with a particle beam interface was used to separate and identify aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and t heir nitrated derivatives (nitro-PAHs). In particular, the behaviour o f nitro-PAHs and of two nitrated biphenyls was checked in terms of ins trumental response. A normal-phase chromatographic system was used, wi th a silica column and heptane-tetrahydrofuran as mobile phase. Electr on impact and positive- and negative-ion chemical ionization (NICI) mo des were used; for nitro-PAHs, the best results were obtained under NI CI conditions. In the flow-injection mode, detection limits as low as pg levels were obtained for 9-nitroanthracene, 3-nitro-9-fluorenone, 1 -nitropyrene, 1,8-dinitronaphthalene, 2,7-dinitrofluorene and 2,7-dini tro-9-fluorenone, whereas the low-molecular-mass 1- and 2-nitronaphtha lene were not detected even at mu g levels; using the analytical colum n, a detection limit five times higher was determined for 1-nitropyren e. For most of the nitro-PAHs considered, the dependences of the inten sities on the amounts injected were found to be linear in a range of m ore than two orders of magnitude.