HTC-19 Insights: Why develop HPLC—XRF?

At HTC-19 in Leuven, Belgium, LCGC International spoke to Frederic Lynen and Gaëlle Spileers from the Separation Science Group in the Department of Organic and Macromolecular Chemistry at Ghent University, Belgium about their presentation at the event entitled Advancing HPLC-XRF for the Analysis of Brominated Flame Retardants and Other Pollutants.

In the first part of the interview, Frederic Lynen answered the following questions:

• What was the rationale behind developing high-performance liquid chromatography coupled with X-ray fluorescence (HPLC—XRF) for brominated flame retardant (BFR) analysis ?

• What gap in current chromatographic detection methods motivated this work?

High-performance liquid chromatography coupled with X-ray fluorescence (HPLC–XRF) was recently introduced by our group as a novel elemental detection platform for organobromine compounds.¹ In contrast to conventional detectors, XRF enables universal quantification of brominated analytes without authentic standards and can be readily combined with mass spectrometry (MS) for molecular identification.¹

This research presents an improved HPLC–XRF system with enhanced sensitivity through optimization of the flow cell, tubing configuration, and chromatographic conditions. Tribromophenol was used as a model compound to evaluate analytical performance and establish conditions suitable for brominated flame retardant (BFR) analysis.

BFRs remain important environmental contaminants as a result of their persistence, bioaccumulation potential, toxicity, and widespread occurrence in environmental matrices and biological systems.^1,4-6Regulatory restrictions have reduced the use of several legacy compounds; however, replacement flame retardants and transformation products continue to present analytical and environmental challenges.^5,7–10

While LC–MS and GC–MS provide powerful identification capabilities, quantitative analysis remains dependent on compound-specific standards and can be affected by differences in ionisation efficiency among BFRs.^4,5,7 HPLC–XRF addresses these limitations by providing universal elemental quantification, making it a valuable complementary technique for broad screening of known and emerging brominated pollutants.

The methodology was further evaluated using synchrotron XRF at the European Synchrotron Radiation Facility (ESRF) and applied, together with HPLC–MS, to investigate brominated pollutants in the Scheldt River Basin.

References

1. Spileers, G.; Tack, P.; Vincze, L.; Lynen, F. The Hyphenation of High-Performance Liquid Chromatography with X-ray Fluorescence for Universal, Flow-Through, Elemental Analysis of Organobromines. Anal. Chem. 2025, 97 (43), 23905–23913. DOI: https://doi.org/10.1021/acs.analchem.5c03394.
2. Stockholm Convention Secretariat. Stockholm Convention on Persistent Organic Pollutants. https://chm.pops.int/Home/tabid/10001/Default.aspx (accessed Dec 2, 2025).
3. EFSA Panel on Contaminants in the Food Chain (CONTAM); Hardy, A.; Benford, D.; Halldorsson, T.; et al. Update of the Risk Assessment of Hexabromocyclododecanes (HBCDDs) in Food. EFSA J. 2021, 19(3), e06421. DOI: https://doi.org/10.2903/j.efsa.2021.6421.
4. . Enyoh, C. E.; Maduka, T. O.; Rana, M. S.; Osigwe, S. C.; Ihenetu, S. C.; Wang, Q. Chemicals from Brominated Flame Retardants: Analytical Methods, Occurrence, Transport and Risks. Appl. Sci. 2024, 14 (17), 7892. DOI: https://doi.org/10.3390/app14177892.
5. 5 Li, M.; et al. A Review of Occurrence, Bioaccumulation, and Fate of Novel Brominated Flame Retardants in Aquatic Environments: A Comparison with Legacy Brominated Flame Retardants. Sci. Total Environ. 2024, 939, 173224. DOI: https://doi.org/10.1016/j.scitotenv.2024.173224.
6. Thuy, T. L.; Hoang, T.-D.; Hoang, V.-H.; Nguyen, M.-K. A Review on Flame Retardants in Soils: Occurrence, Environmental Impact, Health Risks, Remediation Strategies, and Future Perspectives. Toxics 2025, 13 (3), 228. DOI: https://doi.org/10.3390/toxics13030228.
7. Martinez, G.; Niu, J.; Takser, L.; Bellenger, J.-P.; Zhu, J. A Review on the Analytical Procedures of Halogenated Flame Retardants by Gas Chromatography Coupled with Single Quadrupole Mass Spectrometry and Their Levels in Human Samples. Environ. Pollut. 2021, 285, 117476.DOI: https://doi.org/10.1016/j.envpol.2021.117476.
8. Sharkey, M.; Harrad, S.; Abdallah, M. A.-E.; Drage, D. S.; Berresheim, H. Phasing-Out of Legacy Brominated Flame Retardants: The UNEP Stockholm Convention and Other Legislative Action Worldwide. Environ. Int. 2020, 144, 106041. DOI: https://doi.org/10.1016/j.envint.2020.106041.
9. Liu, A.; Qu, G.; Yu, M.; Liu, Y.; Shi, J.; Jiang, G. Tetrabromobisphenol A/S and Nine Novel Analogs in Biological Samples from the Chinese Bohai Sea: Implications for Trophic Transfer. Environ. Sci. Technol. 2016, 50 (8), 4203–4211. DOI: https://doi.org/10.1021/acs.est.5b06043.
10. Yang, Y.; et al. Identification and Occurrence of TBBPA and Its Debromination and O-Methylation Transformation Products in Sediment, Fish and Whelks from a Typical E-Waste Dismantling Site. Sci. Total Environ. 2022, 833, 155249. DOI: https://doi.org/10.1016/j.scitotenv.2022.155249.

Biography

Frédéric Lynen is a professor at Ghent University, Belgium, specializing separation sciences and mass spectrometry at the department of organic and macromolecular chemistry at Ghent University. His research comprises high performance liquid chromatography (HPLC), gas chromatography and capillary electrochromatography (CEC), column technology, temperature responsive liquid chromatography, stationary phase synthesis, comprehensive multi-dimensional separations, chromatographic predictive modelling and the development of LC–MS, GC–MS and capillary electrophoresis (CE)-based non-targeted approaches allowing, for example, biomarker discovery. He is the co-author of about 145 journal articles in the field of separation sciences and involved in the organization of the HTC conference series.