The Mechanism of Chromatographic Retention - Mixed Phases > Page 29


The column was 25 cm long, 4.6 mm I.D. and packed with Partisil 10. Linear curves were obtained for three different solutes and two different moderators in n-heptane.

As another example, Scott and Beesley (10) obtained retention data for the two enantiomers, (S) and (R) 4-benzyl-2-oxazolidinone over a range of temperatures. The column was 25 cm long, 4.6 mm I.D. packed with 5 mm silica particles bonded with the stationary phase Vancomycin (Chirobiotic V provided by Advanced Separations Technology Inc., Whippany, New Jersey). Chirobiotic V is a macrocyclic glycopeptide that has a molecular weight of 1449.22, and an elemental composition of 54.69% carbon, 5.22% hydrogen, 4.89% chlorine, 8.70% nitrogen and 26.50% oxygen. It contains 18 chiral centers surrounding three 'pockets' or 'cavities' which are bridged by five aromatic rings and thus can readily offer unique enantiomeric selectivity to a wide range of chiral substances.



Courtesy of the Journal of Chromatography (ref.14)

Figure 13. Graph of Corrected Retention Volume of the (S) 4-Benzyl-2-oxazolidinone against the Reciprocal of the Volume Fraction of Ethanol