A label-free detector for liquid chromatography systems using mm-wave technology: First proof of concept

Area of Science:

• Analytical Chemistry
• Electromagnetics
• Biophysics

Background:

• Millimeter-wave (mm-wave) technology utilizes electromagnetic waves (30-300 GHz) for studying bio-molecular interactions.
• Liquid chromatography (LC) systems require sensitive detection methods for analyzing complex mixtures.
• Existing LC detectors may have limitations in detecting certain types of compounds or require labeling.

Purpose of the Study:

• To explore millimeter-wave technology as an alternative detection technique for LC systems.
• To design and fabricate a label-free mm-wave detector compatible with LC systems.
• To demonstrate the detector's capability in identifying both UV-absorbing and non-UV-absorbing compounds.

Main Methods:

• Development and fabrication of an in-house mm-wave detector.
• Integration of the detector with an LC system using open and packed capillaries.
• Injection of UV-absorbing (praziquantel, trans-stilbene-oxide) and non-UV-absorbing (sorbitol) compounds.
• Comparative analysis using both mm-wave and UV detectors.

Main Results:

• The developed mm-wave detector successfully detected all tested compounds (praziquantel, trans-stilbene-oxide, sorbitol) without labeling.
• The detector demonstrated compatibility with LC systems, functioning with both open and stationary phase capillaries.
• The label-free nature of the mm-wave detection was confirmed.

Conclusions:

• Millimeter-wave technology presents a promising label-free detection approach for LC systems.
• The developed mm-wave detector shows potential as an additional analytical tool for LC.
• Further research is needed to optimize detection limits and verify performance across a wider range of analytes.