Broadband cavity enhanced absorption spectroscopy as a detector for HPLC

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chromatography

Background:

• High-Performance Liquid Chromatography (HPLC) is a vital analytical technique.
• Detection sensitivity in HPLC can be a limiting factor for analyzing low-concentration analytes.
• Cavity Enhanced Absorption Spectroscopy (CEAS) offers high sensitivity for absorption measurements.

Purpose of the Study:

• To demonstrate the first application of a CEAS-based technique for HPLC detection.
• To develop and evaluate a Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS) system integrated with HPLC (HPLC-BBCEAS).
• To assess the sensitivity and detection limits of the developed HPLC-BBCEAS system for dye analysis.

Main Methods:

• Integration of BBCEAS detection with an HPLC system.
• Spectroscopic measurements of rhodamine 6G and rhodamine B dyes in the visible spectrum (450-600 nm).
• Determination of minimum detectable absorption coefficient (αmin) and Limits of Detection (LOD).

Main Results:

• Achieved high sensitivity with αmin values of 2.9 x 10⁻⁵ cm⁻¹ (527 nm) and 1.9 x 10⁻⁵ cm⁻¹ (556 nm).
• Obtained low LODs of 426 pM for rhodamine 6G and 271 pM for rhodamine B.
• Demonstrated 54-77 times lower LOD compared to a conventional HPLC-photodiode array detector.
• Enabled discrimination of nearly co-eluting rhodamine dyes through spectral information.

Conclusions:

• The developed HPLC-BBCEAS system offers significantly improved sensitivity and lower LODs compared to traditional HPLC detectors.
• BBCEAS provides a cost-effective and simpler alternative to existing sensitive HPLC detection methods.
• This technique shows promise for enhanced analysis of analytes in complex mixtures, including nearly co-eluting compounds.