title: On-line two-dimensional LC: a rapid and efficient method for the determination of enantiomeric excess in reaction mixtures.
abstract: A novel LC-based method for the determination of enantiomeric excess (ee) in a sample mixture has been developed by employing on-line 2D LC. The orthogonal separation system is composed of an NH2 column as the first dimension to elute the target chiral compound from the crude mixture and a chiral column as the second dimension to determine the ee of the target chiral product. A series of crude mixtures from asymmetric reactions have been directly analyzed without prepurification. Good reproducibility (intra- and interday precisions were all under 1.33%) and good accuracy (deviations from ee values determined by 1D HPLC were all <1.03%) have been obtained. Compared with the traditional method for the determination of ee, on-line 2D HPLC can be used in real time and holds great potential in the time-saving determination of ee in asymmetric synthesis.
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha, P.R. China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Xinyu
authors.initials: X
authors.lastname: Jiang
authors.forename: Haixing
authors.initials: H
authors.lastname: Zheng
authors.forename: Wen
authors.initials: W
authors.lastname: Su
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D044950:Flavanones / Q000032:analysis* / Q000138:chemical synthesis; D009862:Online Systems; D015363:Quinolones / Q000032:analysis* / Q000138:chemical synthesis
chemical_list: D044950:Flavanones; D015363:Quinolones
keywords: Asymmetric synthesis; Enantiomeric excess; Enantioseparation; HPLC; On-line 2DLC