Quartz Crystal Microbalance as a Holistic Detector for Quantifying Complex Organic Matrices during Liquid...

Area of Science:

• Analytical Chemistry
• Chromatography
• Sensor Technology

Background:

• Complex sample matrices can interfere with trace organic compound analysis.
• High-performance liquid chromatography (HPLC) is crucial for sample cleanup, but optimizing it is challenging due to a lack of real-time matrix detection.
• Gradient elution in HPLC further complicates matrix quantification during cleanup.

Purpose of the Study:

• To explore the potential of quartz crystal microbalance (QCM) dry-mass sensing for quantifying complex organic matrices during gradient HPLC.
• To develop and validate a system for real-time matrix quantification in HPLC cleanup.
• To address the limitations in optimizing HPLC cleanup methods.

Main Methods:

• Coupling a QCM and a microfluidic spray dryer with a commercial HPLC system via a flow splitter.
• Developing a calibration and data processing strategy for the integrated system.
• Characterizing the system's detection and quantification limits for various eluent compositions.

Main Results:

• Achieved detection limits (LOD) of 4.3–15 mg/L and quantification limits (LOQ) of 16–52 mg/L.
• Demonstrated feasibility by validating natural organic matter in an environmental sample against total organic carbon analysis.
• Obtained an absolute recovery of 103 ± 10% for natural organic matter.

Conclusions:

• QCM dry-mass sensing offers a viable solution for real-time matrix quantification during HPLC cleanup.
• The developed system can aid analysts in optimizing HPLC cleanup methods, particularly with gradient solvents.
• This approach holds promise for various analytical fields requiring efficient sample preparation and cleanup.