HPLC - UV-Vis absorption and charged aerosol detection

Importance of the Subject

Dietary supplements and botanical natural products are used worldwide for nutrition and therapeutic purposes, yet their complex matrices and natural variability pose significant challenges for quality control. Reliable analytical methods are essential to ensure product safety, consistency and efficacy.

Study Objectives and Overview

This document reviews high-performance liquid chromatography (HPLC and UHPLC) workflows combined with Charged Aerosol Detection (CAD) and UV-Vis absorbance detection. It illustrates sample preparation strategies, chromatographic separations and detector configurations optimized for a broad array of analytes in dietary supplements and botanical extracts.

Methodology and Instrumentation

The analytical platform integrates:

• Sample Preparation: Accelerated Solvent Extraction (ASE) for efficient, reproducible extraction of solid and semi-solid matrices.
• Separation: A variety of reversed-phase, HILIC and mixed-mode columns (C18, C30, HILIC-10, Trinity P1/P2) delivering high resolution of polar and non-polar compounds.
• Detection: Charged Aerosol Detector for universal, structure-independent response and UV-Vis detectors (VWD, DAD) for chromophoric analytes. Inverse gradient post-column make-up flow ensures uniform CAD response in gradient elution.
• Optional MS: Single quadrupole or high-resolution mass spectrometry for structural confirmation and targeted metabolomics.

Key Results and Discussion

Universal detection by CAD enabled quantitation of non-chromophoric compounds (e.g., triterpenes, glycosides, minerals) using single-standard calibration. Examples include:

• Simultaneous determination of vitamins and minerals in tablets by dual-column CAD/UV workflows.
• Quantification of phytoestrogens (isoflavones, coumestans, lignans) and xanthones in complex botanical matrices.
• Profiling of ginsenosides, boswellic acids, artemisinin, and anthocyanins with sub-nanogram sensitivity and minimal baseline drift.
• Authentication studies using HPLC-CAD coupled with chemometric analysis (PCA) to distinguish authentic samples from adulterants.

Benefits and Practical Applications

Charged Aerosol Detection offers:

• Universal, nearly uniform response across diverse analyte classes without needing individual standards.
• High sensitivity for non-volatile compounds lacking UV chromophores.
• Wide dynamic range and stable baselines in gradient elution (with inverse gradient make-up).
• Compatibility with automated sample preparation and high-throughput UHPLC systems.

Combined with UV-Vis and MS, the platform addresses regulatory requirements for dietary supplement quality control, adulteration detection and product authentication.

Future Trends and Applications

Emerging directions include:

• Integration of CAD-based universal quantitation with untargeted and targeted metabolomics for comprehensive profiling.
• Advanced data analytics and machine learning for pattern recognition and predictive quality assessment.
• Green extraction techniques and miniaturized UHPLC systems for rapid, low-solvent workflows.
• Further coupling with high-resolution mass spectrometry for structure elucidation and novel biomarker discovery.

Conclusion

Innovations in sample preparation, column technologies and detector configurations—especially Charged Aerosol Detection—provide robust, universal and sensitive methods for the analysis of dietary supplements and botanical natural products. These workflows enhance reliability, reduce the need for multiple standards and support regulatory compliance and product integrity.

References

1. Acworth I, et al. Charged Aerosol Detection – Factors Affecting Uniform Response, Thermo Fisher Scientific Application Note TN72806, 2018.
2. Grosse S, et al. Why Use Charged Aerosol Detection with Inverse Gradient? Thermo Fisher Technical Note TN73449, 2020.
3. Zhang T, Wang Y, Gu D, et al. Rapid Securing of Reference Substances from Peucedanum japonicum Thunberg by Recycling Preparative HPLC, Journal of Separation Science, 2019;42(12):2213–2220.