Development of a green analytical method based on a Montmorillonite/Hydroxyapatite composite coupled with rotating disk sorptive extraction and GC–MS for monitoring steroid hormones in hospital wastewater

Abstract

Environmental concern regarding the presence of steroid hormones in hospital wastewater treatment plants underscores the need for effective monitoring and removal strategies. Even at trace levels, steroid estrogens exhibit strong biological activity and bioaccumulation potential, classifying them as endocrine-disrupting compounds. In this study, a Montmorillonite/Hydroxyapatite (MMT/HAp) composite was proposed as an environmentally friendly and low-cost alternative for the extraction of estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3). Sample preparation was carried out using a green analytical method based on rotating disk sorptive extraction. Considering the complexity of wastewater matrices, analytes were determined using gas chromatography coupled to mass spectrometry (GC–MS) in selective ion monitoring mode. A Doehlert experimental design was applied to optimize the extraction process, yielding the following optimal conditions: extraction time of 87 min, sample volume of 16 mL, and stirring speed of 1080 rpm. Hospital wastewater samples from Manizales (Caldas, Colombia) were analyzed, and concentrations of E1, E2, EE2, and E3 were 7.2, 0.1, 6.7, and 33.2 µg L⁻¹, respectively. Limits of detection ranged from 0.06 to 0.40 µg L⁻¹, and limits of quantification from 0.16 to 1.20 µg L⁻¹. Calibration curves for all analytes showed R² values above 0.98. Recovery values obtained through standard addition calibration ranged from 56 % to 90 %, despite significant matrix effects (–67 to 230). The MMT/HAp composite demonstrated comparable performance to the commercial HLB sorbent, confirming its potential for environmental applications.