Stationary phase effects on retention behavior of phenols in micellar liquid chromatography: perfluorooctane vs. C18

✍ Scribed by Shenyuan Yang; Morteza G. Khaledi

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 696 KB
• Volume: 294
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)80188-6

✦ Synopsis

The usefulness of fluorinated bonded stationary phases is further examined in micellar liquid chromatography (MLC) using cationic micellar eluents. The retention behavior of substituted phenols was investigated in MLC with both a Perfluorooctane (FO) column and a C1s column. It has been found that phenols with electron withdrawing groups (e.g., -CN, -NO, and -COR) have longer retention on the FO column than that on the Cl8 cohnnn. This might be due to the larger specific polar interactions between the solutes and the FO column. The functional group selectivity (7) values of these polar substituents were significantly increased on the FO column. However, phenols with substituted hydrocarbons show shorter retention on the FO column than that on the C,, c&mn. This may be due to the smaller hydrophobic interactions between hydrocarbon substituents and fluorocarbon stationary phase. The simultaneous enhancement of solvent strength and selectivity that has been reported in the SDS hybrid system was also observed in the C,,TAB hybrid system. Thi, is due to the existence of the competing partitioning equilibria in MLC and because of the interactive nature of the two eluent parameters, micelle concentration and the volume fraction of organic solvents; both of which infIuence solvent strength and selectivity. The iterative regression strategy was used to optimize these two mobile phase parameters for a group of phenols using the FO column with the cationic micellar eluents. Excellent agreement was obtained between the observed and the predicated optimum chromatograms using only five initial experiments. This indicates that the easily predictable and highly reproducible retention behavior that has been reported in MLC! systems with the alkyl bonded phases is also observed with fluorocarbon bonded phases and cationic micellar eluents.