In-source fragmentation of partially oxidized mono- and polycyclic aromatic hydrocarbons in atmospheric pressure chemical ionization mass spectrometry coupled to liquid chromatography

Partially oxidized derivatives of polycyclic aromatic hydrocarbons (PAHs) a re known to be important environmental pollutants, For the identification o f these substances in complex mixtures, e.g. atmospheric aerosol samples, l iquid chromatography/mass spectrometry with atmospheric pressure chemical i onization (LC/APCI-MS) has been found to be a suitable analytical technique . In this study 31 derivatives of mono- and polycyclic aromatic hydrocarbon s with up to five condensed aromatic rings carrying different functional gr oups (carboxyl, dicarboxylic anhydride, lactone, hydroxyl, and carbonyl) we re characterized by LC/APCI-MS, Each substance was measured in positive and negative ion detection mode at four different fragmentor voltages (90 to 1 90 V). For the first time, the results show that characteristic and well-in terpretable fragmentation patterns can be obtained for these classes-of com pounds by in-source collision-induced dissociation in a single quadrupole L C/APCI-MS system. For each class of compounds typical spectral features and optimum measurement conditions are reported, and fragmentation pathways ar e proposed. The study demonstrates the applicability of LC/APCI-MS for the determination of most of the investigated compounds at trace levels, and it provides a database for the identification of unknown partially oxidized a romatic hydrocarbons. Copyright (C) 1999 John Wiley & Sons, Ltd.