Unique selectivity of tetrahydrofuran-2-propanol-water ternary mobile phases on a superficially porous particle column in reversed-phase liquid chromatography.

Three mixed mobile phase organic modifiers, tetrahydrofuran: 2-propanol 1:1 (v/v), tetrahydrofuran: 2-propanol: 1:3 (v/v), and tetrahydrofuran: 2-propanol: 3:1 (v/v) were studied at 20-70% (v/v) total organic solvent compositions. The solvent strength parameters for the three mixed organic modifiers and system properties were compared to those of more established binary solvent systems, acetonitrile-water and methanol-water. To interpret intermolecular interactions responsible for retention for the three mixed mobile phase organic modifiers, system maps were constructed and compared with acetonitrile and methanol. Three mixed organic mobile phase modifiers on one stationary phase chemistry (Kinetex C18) provide different selectivity than the more established acetonitrile and methanol mobile phase modifiers on the same stationary phase (Kinetex C18) as well as different stationary phase chemistries (Kinetex Biphenyl, Kinetex Phenyl-Hexyl, Kinetex F5, Kinetex XB-C18, and Kinetex EVO C18). The solvation parameter models for all three mixed mobile phase systems the coefficient of determination ranged from 0.991 to 0.999, the Fisher statistic from 338 to 1850, and the standard error of the estimate ranged from 0.024 to 0.097.