Liquid Chromatographic Separation of MM 302 Da Polycyclic Aromatic Hydrocarbons in Synthetic Mixtures Using Chiral Stationary Phase Material

Abstract

High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) are an example of a family of compounds that exist with isomeric mixtures. While multi-instrument techniques may isolate many isomeric PAHs at qualitative and quantitative levels, complete separation of this class of environmental pollutant has not yet been attained, leaving ample room for method improvement. In this research, the separation of 21 commercially available isomers of MM 302 Da was studied using polysaccharide-based chiral immobilized materials as stationary phase. Isocratic, normal phase runs were performed using mixed concentrations and combinations of 302 Da PAH isomers. Retention times and calibration data were determined using a chiral chromatographic setup. Selectivity values are given for all the evaluated HMW-PAH isomers, retention and intensity factors were also calculated based on the directions outlined in Environmental Protection Agency Method 550.1, along with chromatographic peak resolution values. With the use of chiral separation, a total of 16 HMW-PAH peaks are visible on the chromatogram of the 21 MM 302 Da PAH synthetic mixture. This group of molecules does not possess chiral centers in the classical sense; however, larger molecules such as these may possess pseudochiral characteristics, providing a little-researched opportunity for separation strategy of formerly considered achiral molecules to be separated using chiral stationary phases. The resolution of this method makes it suitable for the identification and quantitation of MM 302 Da PAH isomers fractionated from a larger complex sample. The potential for this approach with other classes of high molecular weight achiral molecules is yet to be explored.

Keywords:

• Chiral chromatography
• normal phase liquid chromatography
• polycyclic aromatic hydrocarbons
• polysaccharide column
• process analytical technique

Acknowledgments

The authors thank Chiral Technologies Inc. (West Chester, PA, USA) for the donation of the chiral column used in these studies.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge financial support for this project in part from the Gulf of Mexico Research Initiative grant number 231617-00. The views expressed here are those of the authors and do not reflect the view of the organization.