Institution: | a Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche (CNR), Area della Ricerca di Roma, P.O. Box 10, 00016 Monterotondo Scalo, Rome, Italy b Dipartimento Farmaco Chimico, Facoltà di Farmacia, Università di Messina, Viale Annunziata, 98168, Messina, Italy c Dipartimento di Studi Farmaceutici, Università degli Studi di Roma ‘La Sapienza’, P. le A. Moro 5, 00185, Rome, Italy |
Abstract: | A new chiral stationary phase (CSP) was prepared by reacting MDL 63,246 (Hepta-Tyr), a glycopeptide antibiotic belonging to the teicoplanin family, with 5-μm diol-silica particles. The CSP mixed with 5-μm amino silica particles (3:1) was packed into 75-μm fused-silica capillaries for only 6.6 cm and used for electrochromatographic experiments analyzing several hydroxy acid enantiomers. A reversed electroosmotic flow carried both analytes and mobile phase towards the anode in a short time (1–3 min), being baseline resolved all the studied analytes. In order to achieve the fastest enantiomeric resolution of the studied hydroxy acids, the effect of several experimental parameters such as mobile phase composition (organic modifier type and concentration, pH of the buffer and ionic strength), capillary temperature and applied voltage on enantioresolution factor, retention time, enantioselectivity were evaluated. The packed capillary column allowed the separation of mandelic acid enantiomers in less than 72 s with resolution factor Rs=2.18 applying a voltage of 30 kV and eluting with a mobile phase composed by 50 mM ammonium acetate (pH 6)–water–acetonitrile (1:4:5, v/v). The CSP was also tested in the capillary liquid chromatography mode resolving all the studied enantiomers applying 12 bar pressure to the mobile phase 50 mM ammonium acetate (pH 6)–water–methanol–acetonitrile, 1:4:2:3, v/v)], however, relatively long analysis times were observed (12–20 min). |