Highly fluorinated stationary phases for analysis for polyfluorinated solutes by reversed-phase high-performance liquid chromatography

Abstract

Two perfluorinated stationary phases were prepared by reacting two perfluoroalkyl amlnosilanes (RFC2H4SI(CH3)2N-(CH3)2 with Rf = C8F17 or C10F21) with Lichrosorb S1100 (10 µ ). The chromatographic properties of such stationary phases were checked with perfluoroalkylated series and corresponding hydrogenated series of compounds and compared with a classical C18 stationary phase. The perfluoroalkylated series Included Iodides (RFI), iodoethanes (RFCH2CH2I), and ethenes (RFCH=CH2), RF ranging from C2F5 to C10F21. The plots of log k', the capacity factor, versus the number of carbon atoms produced straight lines for each series and each stationary phase. With a ternary THF-DMF-water (200/50/70 (v/v/v)) mobile phase, the transfer energy per CF2 group was found to be about 1 kJ/mol, with the fluorinated stationary phases, compared to only about 0.35 kJ/mol with the hydrogenated stationary phase. It was also 0.35 kJ/mol for a CH2 group, whatever the phase. This leads to significant Increases In retention times and separation factors of the perfluoroalkylated compounds on the fluorinated phases. The analytical capabilities of such phases were demonstrated by two examples of fluorinated surfactant analysis.

Interpretation of the chromatographic behavior of perhydrogenated and perfluorinated polyoxyethylene surfactants by molecular modeling

“…One can conclude that using this hydro-organic mobile phase, seven CF2 or CF3 increments are equivalent to nine CH2 or CH 3 increments and that six CF2 or CF 3 increments with an oxygen atom replaced by a sulfur atom are equivalent to eight CH2 or CH3 increments. The greater retention of the perfluorinated surfactants in comparison with the perhydrogenated surfactants corroborates RPLC results published by Krafft [21] for perfluorinated iodides and by Gilpin [22] for perfluoroalkanoate esters. For better comparison of compound hydrophobicity, which can be independent of mobile-phase composition, parameters log kw and m corresponding to the linear relationship given by Eq.…”

CEC with new monolithic stationary phase based on a fluorinated monomer, trifluoroethyl methacrylate

“…Fluorinated-bonded-silica-based stationary phases have been commonly used in the reversed phase separations in HPLC [41][42][43][44][45][46][47]. In these studies, the retention properties of fluorinated phases synthesized with different methods were investigated [41][42][43][44][45][46][47].…”

“…In these studies, the retention properties of fluorinated phases synthesized with different methods were investigated [41][42][43][44][45][46][47]. Several studies were also performed on the electroosmotic and retention properties of fluorinatedbonded silica-based particulate stationary phases in electrochromatographic separations [48,49].…”

Synthesis, characterisation and chromatographic evaluation of pentafluorophenyl and phenyl bonded silica phases prepared using supercritical carbon dioxide as a reaction solvent

“…In 1983, Xindu and Carr [29] reported the application of FluoroFlash and FluoroSep-RP Octyl (C 8 F 17 ) for the analysis of proteins using a high percentage of organic modifier in the mobile phase. In 1988, Kraff et al [30] showed that polyfluorinated analytes were better retained on alkyl fluorinated stationary phases and a study by Billiet et al [31] observed enhanced selectivity for some esters and ketones on a fluorinated alkyl phase. Pentafluorophenyl silica bonded phases have been found to possess enhanced retention and special selectivity for aromatic compounds compared to phenyl phases [32,33].…”