Selective microextraction of polycyclic aromatic hydrocarbons using a hydrophobic deep eutectic solvent composed with an iron oxide-based nanoferrofluid

A Theoretical Study on Terpene‐Based Natural Deep Eutectic Solvent: Relationship between Viscosity and Hydrogen‐Bonding Interactions

“…In our previously published work, menthol or thymol was proven to interact with other constituents in eutectic mixtures as both HBA and HBD. [ 32 ] Menthol, thymol, and β‐citronellol (all natural small molecules and terpenoids) can undoubtedly act as mutual HBAs and HBDs in terpene‐terpene based NADES systems. For thymol/β‐citronellol system, the intensity of the RDF in thymol H14‐citronellol O1 is slightly stronger than that of thymol O1‐citronellol H14 due to the strong electrophilic effect of the benzene ring.…”

Deep Eutectic Solvents Application in Food Analysis

“…These hydrophobic solvents consisted of a long chain alkyl quaternary ammonium salt (e.g., tetrabutylammonium chloride (N 4444 Cl), methyltrioctylammonium chloride (N 8881 Cl), tetraheptylammonium chloride (N 7777 Cl), tetraoctylammonium chloride (N 8888 Cl), methyltrioctylammonium bromide (N 8881 Br) and tetraoctylammonium bromide (N 8888 Br)) and poorly soluble carboxylic acids (e.g., decanoic acid), and their extraction capacity was evaluated by extracting volatile fatty acids from diluted aqueous solutions. Since then, multiple HDESs based on neutral compounds have also been proposed, including combinations of monoterpenes with fatty acids [85], tetraalkylammonium halides with fatty acids and alcohols [86,87], fatty acids with fatty acids [88], and monoterpenes with monoterpenes [17]. Many of the HDESs have also been designed and classified following the same classification that had been previously proposed and that was already used for hydrophilic DESs (type I, II, III and IV), but due to their need to be stable in the aquatic environment, they are mainly grouped into type III (a combination of a quaternary salt (HBA) with a HBD) and type IV (a combination of metal chloride with HBD) [89].…”

“…[120] In general, all the DESs included in the table have been synthesized following the same guidelines as for hydrophilic DESs: mixing the components while heating with constant stirring until a homogeneous mixture is obtained. In addition, although most HDESs used in food analysis are made up of two components, some ternary DESs have been designed, which show numerous advantages over traditional DESs, such as a lower viscosity and melting point, and even a better extraction efficiency in some cases [17,114]. It is the case of the work of Shishov and co-workers [103], in which different quaternary ammonium salts, carboxylic acids and medium chain fatty acids were studied as components of a DES.…”

“…Apart from the previously described, and despite the broad spectrum of DESs that can be synthesised, few information about the methodology to follow for the choice of the components of a DES to be used for specific applications can be found in the literature. Generally, hydrophilic DESs are suitable for the extraction of analytes from low-polar food samples, such as edible oils [13], fish [14] or rice flour [15], while HDESs are adequate for the extraction of inorganic and organic compounds from aqueous food samples, such as fruit juices [16], coffee [17] or tea beverages [18]. However, in certain cases, they can also be used in other matrices if a suitable dispersing or emulsifying agent is added to facilitate the analytes extraction, so this rule is not always fulfilled.…”

Polycyclic aromatic hydrocarbons in coffee samples: Enquiry into processes and analytical methods

“…A fast and environmentally friendly method that is based on a pretreatment method involving hydrophobic natural deep eutectic solvents (NADES) and ultra-small iron-oxide-based nanoferrofluids has been described for selective PAHs microextraction (Fan et al, 2019). 14 PAHs were determined in 12 coffee-bean samples roasted under different conditions (light, medium, full-city and Italian roasting).…”