A new liquid chromatography–tandem mass spectrometry method using atmospheric pressure photo ionization for the simultaneous determination of azaarenes and azaarones in Dutch river sediments

• New LC–APPI/MS/MS method for azaarenes and their degradation products was developed.
• PAHs, PANHs and hydroxyl-PANHs were measured together in one LC–MS/MS run.
• Fresh water and sediment samples were prepared and analyzed.

A new method for the analysis of azaarenes and their degradation products (azaarones) was developed, optimized and validated using liquid chromatography coupled with atmospheric pressure photo ionization tandem mass spectrometric detection (LC–APPI/MS/MS). Seventeen compounds including 4 PAHs (naphthalene, anthracene, phenanthrene, benz[a]anthracene), 7 azaarenes (quinoline, acridine, phenanthridine, 5,6-benzoquinoline and 7,8-benzoquinoline, benzo[a]acridine, benzo[c]acridine), and 6 azaarones (2-OH-quinoline, 4-OH-quinoline, 5-OH-quinoline, 6-OH-quinoline, 9(10H)-acridone, 6(5H)phenanthridinone) were analyzed in sediment samples from Dutch rivers. All compounds were analyzed simultaneously in multi reaction monitoring (MRM) mode. Soxhlet extraction was used for the extraction of analytes from sediments. The limits of quantification of azaarenes and azaarones varied from 0.21 to 1.12 μg/l and from 0.23 to 1.58 μg/l, respectively. The limits of quantification for PAHs varied from 32 to 769 μg/l. Matrix-independent recoveries of sediment samples were in the range 85–110%; matrix-dependent recoveries were in the range 73–148%, respectively. The method was tested on real sediment samples and the results were compared with a previous study in which GC/MS/MS was used for the simultaneous measurement of azaarenes and azaarones. 4-, 5- and 6-OH-quinolines and naphthalene, anthracene and phenanthrene were not present or below detection limits in some samples. All other analytes were present in samples in the concentration range 0.2–1200 ng/g (dw). To our knowledge, this is the first report showing the possibility of measurement non-polar polyaromatic hydrocarbons together with polar azaarenes and their degradation products azaarones simultaneously with sufficient sensitivity and accuracy using LC/MS/MS.