Toribio L, del Nozal M J, Bernal J L, Cristofol C, Alonso C
Department of Analytical Chemistry, Faculty of Science, University of Valladolid, Prado de la Magdalena s/n, 47005 Valladolid, Spain.
J Chromatogr A. 2006 Jul 21;1121(2):268-73. doi: 10.1016/j.chroma.2006.04.008. Epub 2006 May 2.
The enantiomeric separation of cetirizine and oxfendazole on a Chiralpak AD column using subcritical fluid chromatography has been studied in this work. The enantioseparation of cetirizine was only possible when 2-propanol was used as a modifier, obtaining better results in presence of the additives triethylamine (TEA) and trifluoroacetic acid (TFAA). On the contrary, 2-propanol provided the lowest enantioresolutions for oxfendazole, in this case the best results in terms of high resolution and short analysis time were obtained with ethanol. The study of the temperature effect revealed that in the case of cetirizine using 2-propanol, and oxfendazole using methanol, the separation was enthalpy-driven and the isoelution temperature was above the working range. Using ethanol or 2-propanol, the results showed that the oxfendazole enantioseparation was entropically driven and the isoelution temperatures were below the range studied.
