Chiral detection in high-performance liquid chromatography by vibrational circular dichroism

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chromatography

Background:

• Chiral compounds require specialized detection methods in chromatography.
• Vibrational circular dichroism (VCD) offers a unique approach to chiral analysis.
• Existing VCD detection methods may have limitations in sensitivity or universality.

Purpose of the Study:

• To develop and characterize a novel chiral detector for high-performance liquid chromatography (HPLC).
• To utilize infrared vibrational circular dichroism (VCD) for sensitive chiral detection.
• To demonstrate the detector's capability in identifying chiral compounds with O-H groups.

Main Methods:

• Development of a novel HPLC detector based on VCD measurements in the infrared region (2.4–3.5 microns).
• Utilized a tunable F-center laser, photoelastic modulator for circular polarization, and an indium antimonide detector.
• Employed double modulation (85 Hz chopper and 42 kHz photoelastic modulator) with lock-in amplifiers for noise reduction.

Main Results:

• The instrument successfully measured VCD of O-H groups.
• Achieved high sensitivity, detecting microgram quantities of chiral compounds like (R/S)-2,2,2-trifluoro-1-(9-anthryl)ethanol and (R/S)-benzoin.
• Demonstrated chiral detection of separated enantiomers from racemic mixtures using a Chiralcel-OD column.

Conclusions:

• A novel, highly sensitive, and universal chiral detector for HPLC based on VCD has been developed.
• The detector is capable of identifying chiral compounds containing O-H groups, including aliphatic alcohols.
• This technology represents a significant advancement in chiral analysis, offering broad applicability.