Micro-solvent cluster extraction using aqueous mixed solvents of ionic liquid.
Organic compounds (2-naphthol, phenol, 4-chlorophenol, 4-nitrophenol, and 1,3,5-naphthalenetrisulfonic acid) were sufficiently separated from mixtures during flow in a fused silica capillary tube (50 microm in i.d. and 45 cm in length) with an aqueous mixed solvent of an ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIM(+)Cl(-)), without a specific separation column. The method is based on micro-solvent cluster formation in aqueous mixed solvents of ionic liquid and preferential solvation of solvent clusters to analytes. The measurement of large angle X-ray scattering (LAXS) of aqueous mixed solvents with an ionic liquid of tetrafluoroborate (BMIM(+)BF(4)(-)) indicated the formation of micro-solvent clusters of water and ionic liquid in the mixed solvent. A neutral polymer (polyvinylpyrrolidone, PVP) enhanced the separation. Polarized or ionic molecules eluted slowly. The theoretical plate numbers were 6320, 22907, 63645, and 37184 for 2-naphthol, phenol, 4-chlorophenol, and 4-nitrophenol, respectively, under the conditions of 1.0 M of BMIM(+)Cl(-) and 0.1 M of PVP; the flow rate was 1 microL min(-1). The separation mechanism is discussed from the viewpoint of the partition of analytes between micro-solvent clusters of water and organic solvent molecules.
Department of Chemistry, Faculty of Science and Engineering, Saga University, Japan.
Thiraporn
T
Charoenraks
Masaaki
M
Tabata
Kenta
K
Fujii
D001881:Borates / Q000302:isolation & purification; D007093:Imidazoles / Q000737:chemistry / Q000302:isolation & purification; D052578:Ionic Liquids / Q000737:chemistry*; D009930:Organic Chemicals / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
C496308:1-benzyl-3-methylimidazolium; C419324:1-butyl-3-methylimidazolium tetrafluoroborate; D001881:Borates; D007093:Imidazoles; D052578:Ionic Liquids; D009930:Organic Chemicals; D012997:Solvents; D014867:Water