Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Metal organic framework composite, nano-Fe 3 O 4 @Fe-(benzene-1,3,5- tricarboxylic acid), for solid phase extraction of blood lipid regulators from water E.M. Peña-Méndez a,∗ , R.M. Mawale a,b , J.E. Conde-González a , B. Socas-Rodríguez a , J. Havel b , C. Ruiz-Pérez c,1 a Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206, La Laguna, Spain b Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A14, 625 00, Brno, Czech Republic c Department of Physics, Faculty of Science, University of La Laguna, Campus de Anchieta, 38071, La Laguna, Tenerife, Spain ARTICLE INFO Keywords: Magnetic MOF composite Fibric derivative compounds Water cleaning ABSTRACT The magnetic metal-organic framework Fe 3 O 4 @(Fe-(benzene-1,3,5-tricarboxylic acid) (MMOF) was prepared, characterized and studied as a magnetic sorbent for the dispersive solid-phase extraction (DSPE) of several widely used blood lipid regulators (i.e., bezafbrate, clofbric acid, clofbrate, gemfbrozil and fenofbrate) from water samples. Characterization of the synthesized Fe 3 O 4 @Fe-BTC magnetic nanomaterial was performed by Fourier transform infrared spectroscopy, powder X-ray difractometry, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The magnetic nanocomposite was found to be chemically stable and to possess a large surface area (803.62 m 2 /g) and pore volume (0.59 cm³/g). The con- centrations of fbrates in diferent water samples were determined using HPLC-UV-Vis and confrmed by UPLC- MS/MS. Parameters afecting the extraction efciency of magnetic-DSPE were studied and optimized. The maxima absorption capacities (Q max ) were determined to be (in mg/g) 197.0 for bezafbrate, 620.3 for clofbric acid, 537.6 for clofbrate, 288.7 gemfbrozil and 223.2 for fenofbrate. Validations of the optimized magnetic DSPE method for analyses at two fbrate concentrations in spiked water samples produced relative recovery values ≤ 70% for clofbrate and within the range of 80–100% for bezafbrate, clofbric acid, gemfbrozil and fenofbrate. LODs ranging from 4 μg/L for fenofbrate to 99 μg/L for gemfbrozil were obtained. The validated methodology produced recovery values ranging from 70 to 112% (relative standard deviations < 7%). 1. Introduction Blood lipid regulators, such as bezafbrate, fenofbrate, clofbrate and gemfbrozil, belong to a category of pharmaceuticals that are commonly found in aquatic environments, including potable water re- servoirs [1–3]. These regulators are extensively used as drugs not only for the treatment of high cholesterol levels but also for postmenopausal complications and cardiovascular diseases. One of their metabolites, 2- (4-chlorophenoxy)-2-methyl propanoic acid (clofbric acid), has also been applied as an herbicide and plant growth regulator [4], and maximum concentration limits for this compound in drinking water have been set by the Environmental Protection Agency (EPA). Fibrates are mainly released into the environment through the efuent dis- charge of wastewater treatment plants (WWTPs) [3,5] and become potential underwater contaminants due to their recalcitrant behaviors [6,7]. Indeed, bezafbrate has been detected in wastewater efuents in the United Kingdom at levels ranging between 177 and 418 ng/L [8] and at a concentration of 3100 ng/L in surface waters [9]. Regarding gemfbrozil, concentrations in the range of 0.04–0.3 ng/L have been reported in the seawater at Galway Bay, Ireland [10]. Moreover, con- centrations in the range of 0.08–19.4 mg/L have been detected in wastewater efuents, and concentrations of up to 6.86 mg/L have been detected in groundwater in Texas [11]. The impacts of these compounds on the environment are not well known [11]. Corcoran et al. [12] recently found that clofbric acid is pharmacologically active in carp exposed to doses comparable to the levels found in the aquatic environment, and Rosal et al. [13] demon- strated the substantial toxicities of fenofbric acid for Vibrio fscheri https://doi.org/10.1016/j.talanta.2019.120275 Received 7 May 2019; Received in revised form 13 August 2019; Accepted 15 August 2019 ∗ Corresponding author. E-mail address: empena@ull.edu.es (E.M. Peña-Méndez). 1 Deceased author (In memorian). Talanta 207 (2020) 120275 Available online 29 August 2019 0039-9140/ © 2019 Published by Elsevier B.V. T