关键词:
supercritical fluid chromatography (SFC)
stationary phases classification
unified chromatography
reversed-phase
normal-phase
linear salvation energy relationship (LSER)
salvation parameter model
SOLVATION ENERGY RELATIONSHIPS
POROUS GRAPHITIC CARBON
SILICA GEL COLUMN
LIQUID-CHROMATOGRAPHY
PARAMETER MODEL
MOBILE-PHASE
RETENTION CHARACTERISTICS
SOLUTE DESCRIPTORS
INTERNAL STANDARDS
POLAR COMPOUNDS
摘要:
The use of supercritical fluids as chromatographic mobile phases allows to obtain rapid separations with high efficiency on packed columns, which could favour the replacement of numerous HPLC methods by supercritical fluid chromatography (SFC) ones. Moreover, despite some unexpected chromatographic behaviours, general retention rules are now well understood, and mainly depend on the nature of the stationary phase. The use of polar stationary phases improves the retention of polar compounds, when C18-bonded silica favours the retention of hydrocarbonaceous compounds. In this sense, reversed-phase and normal-phase chromatography can be achieved in SFC, as in HPLC. However, these two domains are clearly separated in HPLC due to the opposite polarity of the mobile phases used for each method. In SFC, the same mobile phase can be used with both polar and nonpolar stationary phases. Consequently, the need for a novel classification of stationary phases in SFC appears, allowing a unification of the classical reversed-and normal-phase domains. In this objective, the paper presents the development of a five-dimensional classification based on retention data for 94-111 solutes, using 28 commercially available columns representative of three major types of stationary phases. This classification diagram is based on a linear solvation energy relationship, on the use of solvation vectors and the calculation of similarity factors between the different chromatographic systems. This classification will be of great help in the choice of the well-suited stationary phase, either in regards of a particular separation or to improve the coupling of columns with complementary properties. (c) 2008 Elsevier B.V. All rights reserved.