The Influence of the Aromatic Character in the Gas Chromatography Elution Order: The Case of Polycyclic Aromatic Hydrocarbons

A link between the aromatic character of polycyclic aromatic hydrocarbons and gas chromatography elution order in columns with a polysiloxane backbone in the stationary phase is reported for the first time. The aromatic character was calculated using a method that combines the π-Sextet Rule and the Pauling Ring Bond Orders to allow the establishment of the location and migration of aromatic sextets in PAH structures. One GC column with a polysiloxane - like backbone (Rxi-PAH) and three GC columns with a polysiloxane backbone (DB-5, SE-52, and LC-50), were used for the analysis. According to the results of this study, within an isomer group, PAHs that contain a lower number of rings affected by the aromatic sextets tend to elute earlier than PAHs that contain a higher number of rings affected by the aromatic sextets. The PAHs that follow the calculated elution order are 88 % in the Rxi-PAH column, 88 % in the DB-5 column, 93 % in the SE-52 column, and 85% in the LC-50 column. It is expected that future analyses with other aromatic compounds in GC columns with a polysiloxane backbone in the stationary phase will follow a GC elution order that agrees with the aromatic character of the molecules.