Uses a chiral stationary phase to separate enantiomers.
The retention times differ for each enantiomer, allowing for quantification of enantiomeric excess.
This is the work horse of big pharma.
2. Gas Chromatography (GC) with Chiral Columns
Similar to chiral HPLC, but uses a gas phase for separation.
Useful for volatile compounds, with enantiomers separated based on interactions with a chiral stationary phase.
Commonly used for small chiral molecules.
3. Nuclear Magnetic Resonance (NMR) Spectroscopy
Chiral shift reagents can be added to differentiate enantiomers by altering their chemical shifts.
Enantiodiscrimination is observed based on distinct peak patterns.
4. Circular Dichroism (CD) Spectroscopy
Measures the differential absorption of left- and right-circularly polarized light.
Used to assess optical activity and estimate enantiomeric excess for chiral compounds.
5. Polarimetry
Measures the rotation of plane-polarized light by a chiral sample.
A simple method to determine optical purity, though not as precise as chromatographic techniques.
Never seen this used. More of an historical or educational use.
6. Capillary Electrophoresis (CE)
Separates enantiomers based on differences in their interactions with a chiral selector in the capillary.
Provides high resolution for small sample volumes.
7. Mass Spectrometry (MS)
Often combined with chromatography (e.g., chiral LC-MS) to analyze chiral compounds.
Used for sensitive and accurate quantification of enantiomers.
8. X-ray Crystallography
Used to determine the absolute configuration of enantiomers.
Effective for solid crystalline compounds, providing detailed structural information.
These methods are essential for accurately assessing the enantiomeric excess and chiral purity of compounds, each with its strengths and suitable applications depending on the nature of the sample.