Determination of OPAHs and PAHs in Particulate Matter from Ambient Air and Engine Emissions Multidimensional Chromatography

Abstract: Particulate matter (PM) is an air pollutant that seriously impacts human health. Epidemiological studies have shown associations between human exposure to urban air PM and lung cancer, respiratory and cardiovascular diseases. Polycyclic aromatic hydrocarbons (PAHs) and oxygenated polycyclic aromatic hydrocarbons (OPAHs) are two groups of compounds associated with PM in ambient air. These compounds are generated from the incomplete combustion of organic material of both natural and anthropogenic origin. PAHs are thought to play an important role in the adverse health outcomes from exposure to PM in air. OPAHs contain one or more carbonyl groups and could be more toxic to humans compared to their corresponding parent PAH. Measurement of these compounds at trace levels in complex matrices requires analytical methods with high selectivity and precision and low quantification limits.This thesis describes the development and application of analytical methods for the determination of PAHs and OPAHs in ambient air and engine exhaust PM. Extraction was performed using pressurized liquid extraction, and two different setups for liquid chromatography–gas chromatography (LC-GC) were employed for automated sample clean-up, separation and detection. The developed methods were validated using standard reference materials issued by the National Institute of Standards and Technology. The first methodology developed used off-line solid-phase extraction and on-line LC-GC/mass spectrometry (LC-GC/MS). This method provided low limits of quantification and high selectivity and was successfully applied to the determination of OPAHs and PAHs in PM from the urban atmosphere of Sulaymaniyah city in the Kurdistan region of Iraq. The concentration of benzo[a]pyrene in Sulaymaniyah city was three times higher than the legislated EU target value (1 ng/m3). Furthermore the analytical method was applied on exhaust PM of vehicles fuelled with various gasoline/ethanol blends. The emissions factors for PAHs and OPAHs were highest when using70% ethanol/gasoline blends at -7 °C.The second method developed provided fully automated clean-up, separation and detection of PAHs in PM extracts using a multidimensional 2D-LC/2D-GC system. Polar, mono/di-aromatic and alkane compounds were successively removed by the two-dimensional LC part of the system. Heart-cutting segments from the first GC column (first dimension) to the second GC column (second dimension) increased the resolution of poorly separated or co-eluted PAHs. The results were in good agreement with the certified values from NIST (±25%).