PCA of Perfluorinated Phases

Recently, there has been much interest in the use of perfluorinated phases as they can offer an orthogonal separation mechanism compared to standard alkyl RP materials. As a consequence of this, the number of commercially available phases has increased dramatically. We have recently characterized and performed PCA on ten alkyl and phenyl perfluorinated silica-based stationary phases using the modified Tanaka approach and compared their retention behavior with that of conventional phenyl and alkyl phases [13]. 

The PC1-PC2 model for the database accotmted for 84% of the chromatographic variability within these phases. The score plot in Fig. 7 illustrates that the perfluorinated phases can be categorized into three subgroups. 

Group A containing the perfluorophenyl phases (e.g.. Discovery F5 HS and Fluophase PFP, column nos. 20 and 26), Group B the perfluorohexyl branched alkyl endcapped (e.g., Fluofix, column no. 24) and perfluoroctyl phases (e.g., Fluophase RP and FluoroSep RP Octyl, column nos. 27 and 28), and Group C the perfluorohexyl non-endcapped (e.g., Fluofix, column no. 25) and perfluoropropyl (e.g., Perfluorpropyl ESI, column no. 72) phases. 

The loading plots indicate that the subgroups possess the following dominant chromatographic properties  

A) High surface area/hydrophobidty, high shape selectivity (kpg, 0C h2 %/o)  

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