Graphene Stationary Phase Integrated With Bio-inspired Polydopamine Polymer For Gas Chromatography

In gas chromatography(GC), exploring selective stationary phases and their coating methods on capillary columns has been in demand for complex samples consisting of diverse types of analytes. Graphene(G), a carbon-based nanomaterial possessing high specific surface area and large delocalized π-electron system, has attracted extensive attention in recent years. The great difficulty of employing graphene as GC stationary phase was to fabricate a high-efficiency column owing to its intrinsic tendency to aggregation.This work innovatively addressed the above problem by pretreating the column with polydopamine(PDA) prior to coating graphene, which had been not reported before. The as-fabricated G-PDA@capillary were investigated regarding chromatographic parameters,separation performance and retention mechanism. The main contents are as follows.(1) The development of GC stationary phases is briefly sketched. Also, the properties and applications of G and PDA are described. The present work is of great significance in exploiting a novel stationary phase for GC separations.(2) The feasibility of the proposed method for fabrication of G-PDA@capillary column was demonstrated by SEM and its separation performance for the mixture of alkanes, alcohols and aldehydes. In addition, two other types of columns, namely G@capillary and PDA@capillary columns, were also prepared for comparison.(3) Chromatographic performance of G-PDA@capillary was evaluated. It was proved that G-PDA@capillary was weakly polar and showed column efficiency of 3406 plates/m.Separation performance of the capillary were investigated by various types of analytes including alkanes, alcohols, esters, aldehydes, PAHs, anilines, the Grob and other mixtures.Particularly, G-PDA@capillary exhibited high selectivity and resolving ability for alkane isomers, alcohol isomers and substituted benzenes with diverse groups. Additionally, the G-PDA@capillary showed good repeatability and thermal stability up to 320℃.This work demonstrated the feasibility of the proposed strategy by integrating graphene sheets with PDA coating, which was efficient in addressing the current problem with graphene sheets and exploring its full potential in GC separations.