Thermal lens-circular dichroism detector for high-performance liquid chromatography

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chromatography

Background:

• Chiral compounds require specialized detection methods for accurate analysis.
• Existing chiral detectors may lack sensitivity or real-time capabilities.
• Circular dichroism (CD) is a key property for characterizing chiral molecules.

Purpose of the Study:

• To develop a novel and ultrasensitive chiral detector for high-performance liquid chromatography (HPLC).
• To utilize the thermal lens effect for measuring circular dichroism (CD) of chiral effluents.
• To provide direct, real-time information on chirality and optical purity.

Main Methods:

• Developed a detector based on measuring circular dichroism via the thermal lens effect.
• Used sequential excitation with left and right circularly polarized laser light (LCPL and RCPL).
• Measured heat generation using a probe laser beam and a lock-in amplifier for the thermal lens-circular dichroism (TL-CD) signal.

Main Results:

• Achieved a detection limit of 7.2 ng for enantiomers of tris(ethylenediamine)cobalt(III).
• Demonstrated real-time measurement of chirality and optical purity.
• Successfully separated and detected enantiomers using ion pair reversed-phase chromatography.

Conclusions:

• The developed TL-CD detector offers high sensitivity and direct chiral information.
• This method is advantageous for analyzing chiral samples in HPLC.
• The detector provides a valuable tool for characterizing optical purity and enantiomeric composition.