Green and simple extraction of free seleno-amino acids from powdered and lyophilized milk samples with natural deep eutectic solvents

Abstract

Natural deep eutectic solvents (NADES) were introduced for the extraction of free selenoamino acids from lyophilized and powdered milk samples. Different NADES were evaluated, and lactic acid:glucose (LGH) showed the highest selenium recoveries. Selenium analysis was performed by inductively coupled plasma mass spectrometry (ICP MS). Se-NADES analysis in ICP MS was optimized according to the radio frequency power and nebulization gas flow rate. Se-NADES extraction was optimized by an experimental design. LGH dilution, LGH volume, sample quantity, and ultrasound time were factors influencing the extraction. Seleno-amino acids were determined by liquid chromatography-ICP MS. After optimization, the limits of detection obtained were 7.37, 8.63, and 9.64 µg kg -1 for selenocysteine, selenomethionine, and seleno-methylselenocysteine, respectively. The NADES-extraction is a green procedure with 2 penalty points in the EcoScale. The method was applied to the analysis of powdered milk, lyophilized Se-fortified sheep milk, and ERM-BD151 skimmed milk powder.

Deep Eutectic Solvents for the Extraction of Bioactive Compounds from Natural Sources and Agricultural By-Products

“…An exhaustive revision of the literature shows that, apart from vegetables, plants, fruits or agricultural by-products, other natural matrices have also served as source of valuable compounds and as occur with previous sources, the use of NADESs as extraction solvents has been also carried out. In this sense, oils obtained from citric, cereals, olives, and palm [40][41][42][43][44][45][46] have been the products most widely evaluated using DESs, although flour [47], eggs [48] and milk [49] as well as nonagricultural by-products [10,50] have been also investigated. As can be seen in Table 3, the studies were focused on the search of different and varied types of molecules including phenolic compounds [40][41][42]46], flavonoids [40,43], terpenoids [10,42,44], proteins [48], lignans [45] or minerals [50].…”

“…[47] In this kind of application, again ChCl was the preferred HBA combined with alcohols, organic acids, sugars or urea [40,41,[43][44][45][46]50] although other quaternary ammonium salts combined with alcohols [42,47,48], lactic acid combined with glucose [49] or terpenes (menthol) together with myristic acid [10] have been also applied. In all cases, natural components were used, thus the application of NADESs has been the choice in the studies developed so far in this area.…”

Deep Eutectic Solvents Application in Food Analysis

“…[60] As can be seen in the table, hydrophilic DESs have been used with very good performances for the preconcentration and extraction of an extensive diversity of analytes, including both organic compounds (i.e., antioxidants [25], polycyclic aromatic hydrocarbons (PAHs) [65], pesticides [53][54][55][56], amino acids [24], phenolic compounds and caffeine [10,35,38,52,60], flavonoids [29,32], anthocyanins [31,34,58], mycotoxins [33,37], aflatoxins [39], sex hormones [36], antibiotics [41], preservatives [67], organophosphorus pesticides (OPPs) [44,57], curcumin [22,25,40,45], polybrominated diphenyl ethers (PBDEs) [43], and organochlorine pesticides (OCPs) [43,72]) and metals (Cd, Zn, As, Sb, Fe, Cu, Se, Mn, Pb, Cr, Co, Hg and Al [11][12][13][14][15]23,[26][27][28]42,[46][47]…”

“…Taking into consideration the GAC principles, the downscaling of sample treatment has shown some advantages, such as low consumption of samples (10 µL-25 mL), low amounts/volumes of reagents and organic solvents (10-400 µL), a reduction and simplification of procedures, and high enrichment factors. For this reason, although some applications in which larger volumes of DES (even reaching 20 mL) can be found [21,24,29,32,35,37,41,58,69], most hydrophilic DESs have been applied in miniaturized liquid-based extraction techniques (see Table 1). In this sense, DESs have been applied in the three main modes of liquid-phase microextraction (LPME): dispersive liquid-liquid microextraction (DLLME), hollow-fibre liquidphase microextraction (HF-LPME) and single drop microextraction (SDME).…”

“…On the other hand, its properties, such as viscosity or density, are those that will allow better or worse retention of the analytes [1,6]. In general, hydrophilic DESs tend to have a relatively high viscosity, which makes an effective mass transfer in the extraction processes difficult, so a common practice to reduce their viscosity to suitable values consists in the addition of a known amount of water to hydrophilic DESs using the heating method [15,21,24,25,29,31,33,35,37], in which known concentrations of the three components (HBD, HBA and water) are mixed under constant stirring in a water bath (generally at 50 • C) until a homogeneous and transparent liquid is obtained. In certain cases, water has even been replaced by an organic solvent, such as ethanol (EtOH) or MeOH [43].…”