Retention studies of sulphated glycosaminoglycan disaccharides on porous graphitic carbon capillary columns

摘要

The retention behaviour of highly polar and charged disaccharide isomers has been studied on porous graphitic carbon columns and experimental parameters were varied over wide a range, including corcentration and type of mobile phase constituents as well as temperature. The hydrophilic and anionic sugar analytes were highly retained on this stationary phase compared to the octadecyl-derivatized silica packings more commonly used. E.g., an increase in retention with polarity of a solute and with temperature was observed. By isotherm measurements and nonlinear fitting of Langmuirian expressions to the experimental data the graphite surface appeared homogeneous with only one kind of active adsorption site for these kinds of compound which was furthermore supported by the linear Van't Hoff plots obtained by varying the temperature. The gain in free energy was found to be entropically driven after determination of the DeltaHdegrees and DeltaSdegrees values. However, enthalpy-entropy compensation behavior was not met. [References: 29]