p-Terphenyl-based rigid stationary phases with embedded polar groups for liquid chromatography

Terphenyls are important building blocks for a wide range of functional molecules. Among the three isomers, p-terphenyl (C18H14) is particularly useful for the construction of optical devices on account of its unique structure. Herein, two rigid stationary phases bearing p-terphenyl as an external moiety and variable embedded carbamate groups ( p-TerC with one embedded carbamate group and p-TerC2 with two embedded carbamate group) were presented. The proposed stationary phases were characterized by various means and evaluated in reversed-phase (RP) mode, using different classes of analytes, in-cluding polycyclic aromatic hydrocarbons (PAHs), alkylbenzenes, 4-alkylbiphenyls, substituted ureas, sul-fonylureas, substituted sulfanilamides and aromatic acids. The comparison with conventional C18, sev-eral other polar-embedded aromatic and C18 equivalents indicated p-terphenyl-based stationary phases were featured by multiple retention mechanisms, involving pi-pi interaction, charge-transfer interaction, hydrogen-bonding and hydrophobic interaction in RP mode. A unusually high specificity to the analytes with linear structures was observed, as exemplified by an irreversible adsorption of tetracene and a read-ily separation of tetraphene and chrysene. The aliphatic linker used in the proposed stationary phases was an influential factor for retentivity, selectivity and column efficiency. Interestingly, p-TerC2 was operable in normal-phase mode for the separation of certain PAHs through polar-related interactions. The linear, rigid polyphenyl structure of p-terphenyl endowed the new stationary phase with distinctive chromatographic properties, in contrast to those of the preceding counterparts bonded with alkyl and/or polynuclear aro-matic moieties.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Among the three isomers, p-terphenyl is particularly useful for the construction of optical devices due to its unique structure. This study presents two rigid stationary phases bearing p-terphenyl as an external moiety and variable embedded carbamate groups, which exhibit multiple retention mechanisms, high specificity to linear analytes, and distinctive chromatographic properties.