Extracting Estrogenic Hormones Using Rotating Disk and Modified Clays

Researchers from the University of Caldas and University of Chile in Manizales, Colombia and Santiago, Chile, respectively, extracted estrogenic hormones in wastewater samples using rotating disk sorption extraction (RDSE) and modified clays. Their findings were published in the Journal of Chromatography Open (1).

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Estrogenic hormones, which are naturally excreted by humans, are believed to be potentially hazardous emerging pollutants and endocrine-disrupting compounds (EDCs). These hormones can also be byproducts of various industrial processes and have been detected in multiple water sources, including lakes, rivers, and wastewater treatment plant influents and effluents. The World Health Organization (WHO) recognizes risks associated with direct exposure to these compounds, which can also be found in food, medicines, cosmetics, and drinking water. Although typically present at low concentrations (<100 ng/L), they can still be harmful. Chronic exposure to these compounds can increase risk of cancer and have adverse impacts on biological and reproductive systems. Traditional water treatment systems typically cannot remove such pollutants, making investigating the effects of estrogen on human health and other species a substantial scientific challenge. There is a need for more efficient methods to detect and remove these compounds from water sources more important.

Hospital wastewater is considered a major source of contamination, with the range of research and patient care activities in these facilities, as well as waste from patients receiving treatment with different substances, introducing numerous compounds into water sources. Though wastewater systems can remove some of these EDCs, incomplete elimination can result in the persistence of estrogens in wastewater affluents, which can subsequently enter surface waters. Conventional extraction methods, such as Rotating Disk Sorption Extraction (RDSE), have been effectively employed in these analyses. RDSE is based on the extraction equilibrium between a sorptive phase and an aqueous phase that are in continuous contact and movement during extraction, offering ease of use, good reproducibility, and shorter extraction times, among other benefits (2). These highly recalcitrant and poorly biodegradable compounds are not easily removed through conventional treatments.

In this study, RDSE was used in modified clays incorporating ionic liquids to detect estrogenic hormones in hospital wastewater treatment plant (HWWTP) samples. Sodium montmorillonite was modified to enhance its extractive capacity by intercalating ionic liquids between interlayers. After extraction, the concentrated analytes were measured using liquid chromatography coupled with photodiode array detection (HPLC-PDA).

The method achieved absolute recoveries of 61% of 17α-ethinylestradiol (EE2), 41%for 17β-estradiol (E2), and 20% for estriol (E3). These findings were lower than the recovery rates found with a commercial C18 sorbent. However, the technique also achieved enrichment factors of 13, 23, and 32 for E3, EE2, and E2, respectively. In wastewater, the intra-disk reproducibility (RSD) was below 12%. The method also provided limits of detection (LODs) and limits of quantification (LOQs) in HWWTP samples of 0.18–0.42 ng mL^-1 for E3, 0.15–0.37 ng mL^-1 for E2, and 0.07–0.16 ng mL^-1 for EE2 when using the modified adsorbents. These findings underscore the utility of the quantification method for monitoring critical pollutants in HWWTPs.

Additionally, the study modified and characterized three natural clay-based adsorbents with different ionic liquids for RDSE use. The clay, which was modified with 1-hexadecyl-3-methylimidazolium tetrafluoroborate, displayed superior performance across the analytes, achieving high recovery percentages for EE2 and E2 in real samples, with competitive results relative to commercial adsorbents. Overall, the results show that clays have significant potential as effective adsorbents for emerging contaminants in water. This can help support efforts to reduce harmful compounds in the environment, safeguarding public health.

References

(1) López-Vargas, C. A.; Richter, P.; Rosero-Moreano, M. Extraction of Estrogenic Hormones in Wastewater Samples by Using Rotating Disk and Modified Clays with Ionic Liquids. J. Chromatogr. Open 2025, 7, 100194. DOI: 10.1016/j.jcoa.2024.100194

(2) Richter, P.; Arismendi, D.; Becerra-Herrera, M. The Fundamentals, Chemistries and Applications of Rotating-Disk Sorptive Extraction. TrAC Trends Anal. Chem. 2025, 7, 100194. DOI: 10.1016/j.jcoa.2024.100194