Normal-phase liquid chromatography retention behavior of polycyclic aromatic sulfur heterocycles and alkyl-substituted polycyclic aromatic sulfur heterocycle isomers on an aminopropyl stationary phase

Abstract

Retention indices for 67 polycyclic aromatic sulfur heterocycles (PASHs) and 80 alkyl-substituted PASHs were determined using normal-phase liquid chromatography (NPLC) on an aminopropyl (NH) stationary phase. The retention behavior of PASH on the NH phase is correlated with the number of aromatic carbon atoms and two structural characteristics have a significant influence on their retention: non-planarity (thickness, T) and the position of the sulfur atom in the bay-region of the structure. Correlations between solute retention on the NH phase and T of PASHs were investigated for three cata-condensed (cata-) PASH isomer groups: (a) 13 four-ring molecular mass (MM) 234 Da cata-PASHs, (b) 20 five-ring MM 284 Da cata-PASHs, and (c) 12 six-ring MM 334 Da cata-PASHs. Correlation coefficients ranged from r = -0.49 (MM 234 Da) to r = -0.65 (MM 334 Da), which were significantly lower than structurally similar PAH isomer groups (r = -0.70 to r = -0.99). The NPLC retention behavior of the PASHs are compared to similar results for PAHs.

Qualitative characterization of three combustion-related standard reference materials for polycyclic aromatic sulfur heterocycles and their alkyl-substituted derivatives via normal-phase liquid chromatography and gas chromatography/mass spectrometry

“…S6. Based on the retention behavior reported by Wilson et al [26], these isomers eluted as expected in three different NPLC fractions. However, the NPLC fractionation procedure did not benefit the identification of this isomer group for these samples since A12T and BbN23T eluted together in F6.…”

“…In the current study, the qualitative characterization of the separation profiles of the three SRM samples performed by GC/MS analysis, with and without NPLC fractionation, to identify a large number of PASHs. The NPLC fractionation procedure applied to the SRM samples in this study is based on retention data reported recently for 67 PASHs and 80 alkyl-substituted (alkyl-) PASHs [26]. In the case of the three-ring PASHs and alkyl-PASHs, the NPLC fractionation procedure provided no additional benefits because all the isomers were present in the same NPLC fraction.…”

Photoluminescence spectroscopy of anthrathiophenes and benzonaphthothiophenes in Shpol'skii matrixes

“…In order to illustrate the potential of TRP for the analysis of PASHs in complex environmental samples, we refer to previous chromatographic work on SRM 1597a recently published by Wilson and co-workers [28,29]. Based on the GC-MS analysis of NPLC fractions, the authors [28,29] S7 shows the strong overlapping between BbN12T and BbN21T in both the spectral and time domains. One possible way to achieve spectral identification of these two compounds in the co-eluted NPLC fraction is to process phosphorescence EEMs with parallel factor analysis (PARAFAC) [48].…”

“…Sample preparation for validation studies included the binary mixtures in Table S7 and test samples consisting of the synthetic mixtures shown in Table S8. All concentrations were adjusted to fit within the ranges often encountered in SRMs [28,29].…”

“…Since many PASHs present similar chromatographic behaviors and the detection schemes are not specific enough to resolve co-eluting PASHs, the unambiguous determination of PASHs requires a combination of normal-phase (NP) and/or reversed-phase (RP) liquid chromatographic (LC) steps prior to GC-MS analysis. Recently, Wilson and co-workers [28,29] developed methodology for the analysis of PASHs and alkyl-PASHs in standard reference materials (SRMs). Due to the complexity of the samples and the co-existence of numerous polycyclic aromatic hydrocarbons and their alkylated homologues, the determination of PASHs was best achieved with the combination of NPLC retention times, GC retention times and mass spectra.…”