Mass Spectrometric Study of Nitro-PAHs (Polycyclic Aromatic Hydrocarbons)

摘要

Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) have been detected in diesel exhaust (1-5), urban air particulate matter (6,7), commercial carbon black (8,9) and photocopier toners (9,10). Nitro-PAHs are a human health concern because some of them are known to be potent bacterial mutagens (5,9-12) and to be carcinogenic in experimental animals (13,14). Analytical methods for nitro-PAHs have included high performance liquid chromatography (2), gas chromatography (GC) with various detectors (8,15), GC/mass spectrometry (MS) operated in the positive ion election impact (EI) mode (4,6,12) and in the negative ion chemical ionization (NICI) mode (6,16). In addition, analysis of nitro-PAHs by high resolution MS (1) and MS/MS (3) have been reported. An alternative mode of MS ionization is negative ion atmospheric pressure ionization mass spectrometry (NIAPIMS). NIAPIMS responds selectively to compounds which have a high electron affinity. Because nitro-compounds have a high electron affinity, they are a class of chemicals well suited for NIAPIMS analysis. Mitchum and Korfmacher (17) have reported on the NIAPIMS of several nitro-PAHs using a Finnigan 4000 GC/NIAPIMS system. Recently, analysis of nitro-PAHs by NIAPIMS/MS has been reported by Fulford and co-workers (3) using a TAGA 6000 instrument. In the report, the initial results of the GC/NIAPIMS analyses of several PAHs are described. These results suggest that the NIAPIMS system provides an alternative method of analysis for nitro-PAHs and offers the advantage of greater selectivity than is found in the conventional (electron impact ionization) GC/MS mode.