Retention behavior of alkyl-substituted polycyclic aromatic sulfur heterocycles in reversed-phase liquid chromatography

Published

July 24, 2016

Author(s)

Walter B. Wilson, Lane C. Sander, M. J. Lopez de Alda, Milton Lee, Stephen A. Wise

Abstract

Retention indices for 79 alkyl-substituted polycyclic aromatic sulfur heterocycles (PASHs) were determined by using reversed-phase liquid chromatography (LC) on a monomeric and polymeric octadecylsilane (C18) stationary phase. Molecular shape parameters [length, breadth, thickness (T), and length-to-breadth ratio (L/B)] were calculated for all the compounds studied. Based on separations of isomeric methylated-polycyclic aromatic hydrocarbons on polymeric C18 phases, alkyl-substituted PASHs are expected to elute based on increasing L/B ratios. However, the correlation coefficients had a wide range of values from r = 0.43 to r = 0.93. Several structural features besides L/B ratios were identified to play an important role in the separation mechanism of PASHs on polymeric C18 phases. First, the location of the sulfur atom in a bay-like-region results in alkylated-PASHs being more retentive than non-bay-like-region alkylated-PASHs, and they elute later than expected based on L/B value. Second, the placement of the alkyl group in the k region of the structure resulted in a later elution than predicted by L/B. Third, highly nonplanar methyl-PASHs (i.e., 1-Me and 11-MeBbN12T) elute prior to the parent PASH (BbN12T).

Citation

Journal of Chromatography A

Pub Type

Journals

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Keywords

alkyl-substituted polycyclic aromatic sulfur heterocycles, liquid chromatography, molecular shape parameters, retention indices

Citation

Wilson, W. , Sander, L. , Lopez, M. , Lee, M. and Wise, S. (2016), Retention behavior of alkyl-substituted polycyclic aromatic sulfur heterocycles in reversed-phase liquid chromatography, Journal of Chromatography A, [online], https://doi.org/10.1016/j.chroma.2016.07.065 (Accessed October 10, 2025)