Using subcritical/supercritical fluid chromatography to separate acidic, basic, and neutral compounds over an ionic liquid-functionalized stationary phase.
We packed an ionic liquid (IL)-functionalized stationary phase--based on 1-octyl-3-propylimidazolium chloride covalently bounded to silica gel--into a 3.2mmx250mm column for the simultaneous separation of acidic, basic, and neutral compounds using carbon dioxide subcritical/supercritical fluid chromatography (SFC), and examined the effects of the pressure, temperature, co-solvents, and additives on the retention behavior of the analytes. The model compounds tested for SFC separation are acetaminophen, metoprolol, fenoprofen, ibuprofen, naphthalene, and testosterone. The data indicate that hydrogen-bonding and hydrophobic interactions between the analytes and the IL-modified stationary phase seem to involve in the separation process. Simultaneous separation of acidic, basic, and neutral compounds via SFC was successful at a co-solvent content of 20% MeOH, a pressure of 110 bar, and a column temperature of 35 degrees C. The relative standard deviations of the retention times and peak areas at 50 ppm were all less than 4 and 8% (n=6), respectively.
Chou
Fu-Min
FM
Department of Chemistry and Biochemistry, National Chung Cheng University, Min-Hsiung, Chia-Yi 621, Taiwan.
Wang
Wei-Ting
WT
Wei
Guor-Tzo
GT
D000143:Acids / Q000302:isolation & purification; D000468:Alkalies / Q000302:isolation & purification; D002138:Calibration; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D052578:Ionic Liquids / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D009930:Organic Chemicals / Q000302:isolation & purification*; D011312:Pressure; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature
D000143:Acids; D000468:Alkalies; D052578:Ionic Liquids; D009930:Organic Chemicals; D012997:Solvents; D012822:Silicon Dioxide; D000432:Methanol