Advanced SPE-UHPLC-MS/MS Method Validated for Detecting Trace Micropollutants in Drinking Water

Standard water treatment plants often struggle to completely filter out tiny contaminants, meaning these chemicals can sometimes end up in our drinking water and pose potential health risks. Because these pollutants are present in such incredibly small amounts, scientists need highly sensitive tools to detect them. To tackle this, researchers at the University of Porto in Portugal developed and tested an advanced method to spot 23 specific microscopic pollutants (MPs) in drinking water. Their new testing process (which coupled offline solid-phase extraction ultra-high performance liquid-chromatography coupled to tandem mass-spectrometry [SPE-UHPLC-MS/MS]) successfully identified 12 medications, nine pesticides, and two ultraviolet (UV) filters—all of which are closely monitored under recent European Union water safety guidelines. A paper detailing their work was recently published in the journal Pharmaceuticals.¹

Issues concerning the scarcity and adequate quality remain major challenges worldwide, with increases in demand stemming from population growth, industrialization, and water-intensive sectors, as well as rising wastewater production and insufficient treatment; all of which are threat to the availability and quality of fresh water, and consequently the production of drinking water.^2,3 Recently, there has been an increase attention directed towards MPs in the water, which typically occur at residual concentrations in the range of ng L⁻¹ to μg L⁻¹.⁴ While the detection of MPs in drinking water has been reported worldwide including in Portugal, comprehensive studies of different regions of Portugal and a wide range of target compounds has reportedly not been conducted until this study.^5-8

With their validated method was applied to 50 drinking water samples collected across Portugal, theresearchers report that their results showedhigh analytical sensitivity, achieving method detection limits below 1.50 ng L^-1. Up to three MPs were detected per sample, with quantifiable concentrations of each ranging from 0.28 to 98.8 ng L^-1. However, benzotriazole and dimoxystrobin exceeded the upper limits of their calibration curves (specifically, concentrations higher than 133 and 117 ng L^-1, respectively) in one and three of the collected samples, respectively. Considering all analyzed samples, four (fluconazole, irbesartan, dimoxystrobin, and benzotriazole) of the 23 target compounds were detected. Hazard quotient values for all detected MPs were well below 0.1.¹

“The validated SPE-UHPLC-MS/MS method,” wrote the authors of the paper,¹ “is suitable for the sensitive determination of MPs in drinking water. Some MPs were detected, with concentrations indicating no expected human health risks under the conditions evaluated.” They go on to state that their findings fill major research gaps in Portugal, where data remain scarce, and support EU recommendations for enhanced surveillance, as well as underscore the urgent need for expanded monitoring programs and preventive measures to improve management of MPs in water intended for human consumption. Further monitoring campaigns, in their opinion, should be conducted in the future, with compounds exceeding the limits of the calibration curves requiring special attention.¹

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References

1. Quintela, I. M.; Gorito, A. M.; Barbosa, M. O. et al. Multi-Residue Determination and Risk Assessment of EU-Relevant Pharmaceuticals, Pesticides, and UV-Filters in Drinking Water. Pharmaceuticals (Basel) 2026, 19 (3), 402. DOI: 10.3390/ph19030402
2. The United Nations Relief and Works Agency. United Nations World Water Development Report 2024: Water for Prosperity and Peace [Online]. 2024. https://www.unwater.org/publications/un-world-water-development-report-2024 (accessed 2025-06-20).
3. Schreiber, F.; Donato F. F.; Kemmerich, M. et al. Efficiency of Home Water Filters on Pesticide Removal from Drinking Water. Environ Pollut. 2024, 341, 122936. DOI: 10.1016/j.envpol.2023.122936
4. Barbosa, M. O.; Moreira, N. F. F.; Ribeiro, A. R. et al. Occurrence and Removal of Organic Micropollutants: An Overview of the Watch List of EU Decision 2015/495. Water Res. 2016, 94, 257-279. DOI: 10.1016/j.watres.2016.02.047
5. Muambo, K. E.; Kim, M. G.; Kim, D. H. et al. Pharmaceuticals in Raw and Treated Water from Drinking Water Treatment Plants Nationwide: Insights into their Sources and Exposure Risk Assessment. Water Res X 2024, 24, 100256. DOI: 10.1016/j.wroa.2024.100256
6. Israel Dikobe, P.; Tekere, M.; Masindi, V. et al. Occurrence, Persistence, and Removal of Contaminants of Emerging Concern Through Drinking Water Treatment Processes—A Case Study in South Africa. Environ. Nanotechnol. Monit. Manag. 2024, 22, 100997. DOI: 10.1016/j.enmm.2024.100997
7. 7.Ganaie, M. I.; Jan, I.; Mayer, A. N. et al. Health Risk Assessment of Pesticide Residues in Drinking Water of Upper Jhelum Region in Kashmir Valley-India by GC-MS/MS. Int J Anal Chem. 2023, 2023, 6802782. DOI: 10.1155/2023/6802782
8. Barbosa, M. O.; Ribeiro, A. R.; Pereira, M. F. et al. Eco-Friendly LC-MS/MS Method for Analysis of Multi-Class Micropollutants in Tap, Fountain, and Well Water from Northern Portugal. Anal Bioanal Chem. 2016, 408 (29), 8355-8367. DOI: 10.1007/s00216-016-9952-7