%0 PDF %T A Complete Library of Retention Indices and Mass Spectra of C1 to C4 PAH and PASH Enables a Critical Evaluation of Environmental Analytics. %A Zeigler, Christian. %8 2017-04-18 %R http://localhost/files/4q77g373t %X Abstract: Polycyclic aromatic hydrocarbons (PAH), polycyclic aromatic sulfur heterocycles (PASH), and their C1 to C4 substituted analogs are ubiquitous in fossil fuels and pose risk to the environment due to their toxicity. These compounds are also used to identify the source and track the fate of fossil fuels and related pollutants in the environment. Investigators employ gas chromatography/mass spectrometry (GC/MS) to quantify PAH and PASH. Unfortunately, convoluted mass spectra are unavoidable in complex samples. To circumvent this limitation, investigators use selected ion monitoring (SIM) or extraction (SIE). In these modes, signal from only the PAC molecular ion is acquired by the instrument (SIM) or extracted from full scan data (SIE). Identification is based on peak response within a predefined retention window. This work demonstrates SIM/SIE analyses result in faulty concentration estimates due to incorrect assignment of peaks within each homolog. Since few alkylated PAC fragmentation patterns are known, automated sequential GC-GC/MS profiling of coal tar and crude oil provided homolog-specific spectra and defined the retention windows in which these compounds elute. Simultaneous pulsed flame photometric (sulfur-specific) detection differentiated PAH, PASH, and their alkylated homologs when these compounds (co)eluted within the retention windows. The retention behavior of 119 PASH standard compounds on four stationary phases is reported along with their mass spectra, and was used to guide multidimensional GC-GC/MS for compounds where standards were not available. A comprehensive library of spectra and retention indices are reported for the C1 to C4 2-, 3-, and 4-ring PAH and PASH. This library enabled a critical evaluation of SIM/SIE analyses. Differences between SIM/SIE and the multiple fragmentation patterns per homolog (MFPPH) approach ranged from a few percent for C1 compounds to as much as hundreds of percent for the higher alkylated homologs. Incorrect quantification has profound impacts on fate, transport, risk assessment, bioavailability, and weathering studies due to the propensity of PAC to resist natural or active remediation. The data needed for the MFPPH approach, provided herein, serves as the basis for accurate and defensible assessment of PAC concentrations, which will improve environmental forensics and toxicological studies in the future.; Thesis (Ph.D.)--Tufts University, 2012.; Submitted to the Dept. of Chemistry.; Advisor: Albert Robbat.; Committee: Jonathan Kenny, Michele Schantz, and David Walt.; Keyword: Chemistry. %[ 2022-10-11 %9 Text %~ Tufts Digital Library %W Institution