Target and suspect screening of OH-PAHs in air particulates using liquid chromatography-orbitrap high resolution mass spectrometry.
Up until now, the methods used for determination of hydroxylated polycyclic aromatic hydrocarbons in air particulate samples have been target methods, only determining compounds with available reference standards. In this present study, a combined target and suspect screening strategy for the analysis of hydroxylated polycyclic aromatic hydrocarbons was developed, utilizing liquid chromatography coupled to orbitrap high resolution mass spectrometry. The target screening included simultaneous determination of nine hydroxylated polycyclic aromatic hydrocarbons, while additional eight hydroxylated polycyclic aromatic hydrocarbon masses were screened for using the suspect screening. The target screening was validated with respect to linearity, limits of detection and quantification and matrix effects. The calibration curves ranged from 0.01 to 10ng/mL, the method limits of detection and quantification were in the rage of 0.001- 0.018pg/m3and 0.006 - 0.061pg/m3, respectively, while matrix effects ranged from 83% to 104%. For the suspect screening, a list with expected precursor ions created from suspect monoisotopic masses was used. The suspects were then identified by the accurate exact mass, with a mass accuracy threshold <5ppm, molecular formula, isotopic pattern, and mass spectra (fragments) and also semi-quantified in order to obtain information on their relative levels in different matrixes. The developed strategy was applied on five air particulate samples collected from an urban background and five samples from a car tunnel in Stockholm (Sweden). In total 20 hydroxylated polycyclic aromatic hydrocarbons were detected, of which nine compounds were determined using the target screening and 11 were tentatively identified and semi-quantified using the suspect screening strategy. The concentrations of the target compounds ranged from 20.7 to 96.9pg/m3, for most of the analytes the concentrations in particles from car tunnel were slightly higher than in urban air particles. The levels of most of the tentatively identified compounds were also slightly higher in particles from the car tunnel.
Department of Environmental Science and Analytical Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
Rozanna
R
Avagyan
Department of Environmental Science and Analytical Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden. Electronic address: roger.westerholm@aces.su.se.
Roger
R
Westerholm
Air particulates; High resolution mass spectrometry; OH-PAHs; Orbitrap; Particles; Suspect screening