Chiral stationary phase chiracels

A simple, isocratic chromatographic method for the separation, identification, and measurement of etodolac enantiomers without derivitization using chiral stationary phase columns has been reported [25]. A chiral stationary phase column packed with Chiracel OD (cellulose tris-3,5-dimethylphenylcarbamate coated on 10 pm silica gel) was used as the stationary phase. The mobile phase (85 15 v/v, n-hexane/2-propanol (containing 0.1% trifluoroacetic acid)) was pumped at 0.7 mL/min and the UV detection was set at 230 nm. The (-)-(/ )-etodolac enantiomer eluted first, indicating its stronger interaction between the stationary phase relative to the (+)-(S)-etodolac enantiomer. 

The most successful and broadly applied chiral stationary phases comprise the cellu-lose-and amylose-based phases developed by Okamoto (Chiracel and Chiralpak) (39), brush-type phases developed by Pirkle (40),... 

Chiral chromatography can also be used in order to obtain resolution of stereoisomers from aspartame, its precursors, and its degradation products. Lin et al. (84), using a Chiracel OD column and a mobile phase of 2-propanol -hexane (1 1, v/v), achieved complete separation of aspartame precursors, dd-, dl-, LL-, and LD-[(Z)-AspOS-Bzl)-Phe-OCH3], Motellier and Wainer (85) separated four stereoisomers of aspartame, two of diketopiperazine, and three of aspartyl-phenylalanine using a stationary phase composed of a chiral crown either coated on a polymeric support—CrownPack CR( + )—a mobile phase of aqueous perchloric acid, pH 2.8, and modified... 

By using derivatives of cellulose 3,5-dimethylphenyl carbamate (Chiracel OD) as the chiral phase Bergman measured the enantiopurity of complexes of molybdenum (2.45) and iridium (2.46) (Figure 2.67). With the same type of stationary phase, Gladysz measured the ee of rhenium complexes ReCp(NO)P(C6H5)2Br (2.13), and uranyl-salophen complexes of uranium were analysed with a Chiracel ODH column. 

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