Analysis of nitrated polycyclic aromatic hydrocarbons by liquid chromatography with fluorescence and mass spectrometry detection: air particulate matter, soot, and reaction product studies

Abstract

Polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH) are environmental pollutants which pose a threat to human health even at low concentration levels. In this study, efficient analytical methods for the analysis of nitro-PAH and PAH (extraction, clean-up, chromatographic separation, and spectrometric detection) have been developed, characterized, and applied to aerosol samples. The separation and quantification of 12 nitro-PAH was carried out by reversed-phase high performance liquid chromatography (HPLC), on-line reduction, and fluorescence detection. The detection limits were in the range of 0.03-0.5 microg L(-1) (6-100 pg in the investigated sample aliquots), and the recovery rates from soot samples were 70-90%. Nitro-PAH and PAH concentrations have been determined for different types of soot and for urban, rural, and alpine fine air particulate matter (PM2.5). For the first time, trace amounts of nitro-PAH have been detected in a high-alpine clean air environment. The on-line reduction and fluorescence technique has been complemented by atmospheric pressure chemical ionization time-of-flight mass spectrometry (APCI-TOF-MS). The MS detection allowed the analysis of partially nitrated and oxygenated PAH in laboratory studies of the heterogeneous reaction of PAH on soot and glass fiber substrates with gaseous nitrogen oxides and ozone. It led to the tentative identification of a previously unknown nitrated derivative of the particularly toxic PAH benzo[ a]pyrene (BaP-nitroquinone), and provides the first experimental evidence that PAH-nitroquinones can be formed by reaction of PAH with atmospheric photooxidants.

Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions – Part 2: Exemplary practical applications and numerical simulations

“…3.1. In scenarios SS1-2 to SS1-5 the increase of [X 2 ] gs enhances the total sorption layer coverage, θ s , and and significantly decreases α s,X1 , θ s,X1 , and γ X1 for X 1 gas phase concentrations up to [X 1 The outlined effects of competitive co-adsorption are consistent with the experimental data reported by for H 2 O and O 3 interacting with soot aerosol particles (K ads,H2O K ads,O3 ), and more recent observations for NO 2 and O 3 (K ads,NO2 ≈K ads,O3 ; publication of measurement data in preparation; preliminary results reported by Pöschl, 2002, andSchauer et al, 2004). Model system SS3 is analogous to SS2, except that X 1 undergoes self-reaction rather than reaction with quasi-static surface components.…”

Raman Microspectroscopic Analysis of Size-Resolved Atmospheric Aerosol Particle Samples Collected with an ELPI: Soot, Humic-Like Substances, and Inorganic Compounds

“…Moreover, this study was focused on the identification and distinction of soot and humic-like substances, which are generally characterized by high thermochemical refractiveness and relatively low susceptibility for oxidation by gaseous reactants. Exposure of these substances to ozone and nitrogen oxides at ambient temperatures is likely to change their surface composition and content of organic trace substances but not their bulk composition and spectral parameters determined by Raman microspectroscopy (Pöschl et al 2001;Schauer et al 2003;Schauer et al 2004;Pöschl, 2005;Messerer et al 2006;Ivleva et al 2007). …”

Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions – Part 1: General equations, parameters, and terminology

“…Atmospheric aerosols and clouds are complex multiphase systems consisting of a wide variety of organic and inorganic chemical compounds -multiple main components and hundreds of trace substances -in gaseous, liquid, and solid form (Seinfeld and Pandis, 1998;Finlayson-Pitts and Pitts, 2000;McMurry, 2000;Raes et al, 2000;Matta et al, 2003;Maßling et al, 2003;Pöschl, 2003;Sciare et al, 2003;Smolik et al, 2003;Schauer et al, 2003Schauer et al, , 2004Schneider et al, 2004;Putaud et al, 2004a, b;Fuzzi et al, 2006;Elbert et al, 2007;Rudich et al, 2007;and references therein).…”

“…Heterogeneous oxidation and nitration reactions lead to the formation or degradation of hazardous aerosol components (Finlayson-Pitts and Pitts, 1997;Letzel et al, 2001;Pöschl, 2002a;Schauer et al, 2004;Franze et al, 2005;Gruijthuijsen et al, 2006; and references therein), they cause artifacts upon sampling and analysis of air particulate matter (Finlayson-Pitts and Pitts, 2000;Schauer et al, 2003;; and references therein), and they play a major role in technical processes and devices for the control of combustion aerosol emissions (Su et al, 2004;Messerer et al, 2004Messerer et al, , 2006Ivleva et al, 2007;and refernces therein).…”