Talanta 269 (2024) 125401 Available online 10 November 2023 0039-9140/© 2023 Elsevier B.V. All rights reserved. Novel reusable and switchable deep eutectic solvent for extraction and determination of curcumin in water and food samples Qamar Salamat a , Mustafa Soylak a, b, c, * a Erciyes University, Faculty of Sciences, Department of Chemistry, 38039 Kayseri, Turkey b Technology Research and Application Center (ERU-TAUM), Erciyes University, 38039 Kayseri, Turkey c Turkish Academy of Sciences (TUBA), Çankaya, Ankara, Turkey A R T I C L E INFO Keywords: Switchable deep eutectic solvent Curcumin Food samples Microextraction Spectrophotometric analysis ABSTRACT For the frst time, a fast and easy extraction method based on a unique reusable and switchable deep eutectic solvent (made of octylamine, succinic acid, and water as precursors) was presented and utilized for the micro- extraction and determination of curcumin as a model analyte. The main factors used to induce a phase transition in the as-prepared deep eutectic solvent were solutions of NaOH and HCl. Among the standout characteristics of the suggested deep eutectic solvent are the removal of toxic organic solvents like THF, the lack of a need for centrifugation, and the ability to be reused in subsequent extractions. The infuence of effective parameters (i.e., proportions of deep eutectic solvent structure components, volume of prepared deep eutectic solvent, volume and concertation of NaOH, volume of HCl, and salt effect) on the extraction procedure were investigated. The calibration curve also was linear in the range of 35–500 μg L 1 with coeffcients of determination (R 2 ) of 0.9976. Limit of detection (S/N = 3) 10.0 μg L 1 , the limit of quantifcation (LOQ) of 35.0 μg L 1 , the relative standard deviations (RSDs %) composed of intra-day RSD (4.7) and inter-day RSD (6.4), preconcentration factor of 40.0, enrichment factor of 38.68, and relative recovery of 92.6%–100.3 % were achieved. The reusable and switchable deep eutectic solvent based-dispersive liquid-liquid microextraction technique was profciently employed to expedite easy and fast extraction of curcumin from water and food samples. 1. Introduction Turmeric’s dried rhizomes, which belong to the Zingiberaceae fam- ily, have long been used as a food source, natural coloring agent, nutritional spice, and medicinal plant in Asian nations [1,2]. Curcumi- noids are phenolic compounds that are found in abundance in the rhi- zomes and range in concentration from 1 to 6 w/w. They are a combination of curcumin, demethoxycurcumin, and bisdemethox- ycurcumin [3]. Among these Curcuminoids, Curcumin is the compound that is most frequently explored for its properties and uses [4]. Antiox- idant [5], anti-microbial [6], anti-infammatory [7], anti-allergic [8], and anticancer actions [9] are just a few of the pharmacological traits that Curcumin exhibits. Several methods have been widely developed for the determination of curcumin and its derivatives in foods, waters, and pharmaceuticals such as spectrofuorometric [10], spectrophotometry [11–13], liquid chromatography tandem mass spectrometry (LC–MS/MS) [14,15], cy- clic voltammetry (CV) [16,17], reproducible reversed phase high performance liquid chromatography (RP-HPLC) [18], stripping vol- tammetry (AdSV) [19], and capillary electrophoresis technique coupled with a laser induced native fuorescence detection (CE-LINF) [20] Even while the LC-MS/MS is highly sensitive, it is also quite costly, sophisti- cated, and needs to be used by experts in the feld. Furthermore, whereas electroanalytical techniques exhibit selectivity, they also incorporate subjective elements such limited functionality and unstable perfor- mance. When compared to these methods, the spectrophotometer has advantages including affordability, ease of use, quick measurement, and accessibility in the majority of research labs, despite its low sensitivity. Sample preparation, the most crucial step in any analytical proced- ure, is used to preconcentrate traces of chemicals or eliminate matrix- interfering components before measuring them. One sample prepara- tion method that has been recommended is dispersive liquid-liquid microextraction (DLLME), which is quick, easy to use, fexible, and environmentally friendly [21–23]. Depending on the nature of the an- alyte, a variety of solvent types with different polarity have already been utilized in DLLME, including deep eutectic solvents, supramolecular * Corresponding author. Erciyes University, Faculty of Sciences, Department of Chemistry, 38039 Kayseri, Turkey. E-mail address: soylak@erciyes.edu.tr (M. Soylak). Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta https://doi.org/10.1016/j.talanta.2023.125401 Received 14 September 2023; Received in revised form 16 October 2023; Accepted 7 November 2023