Aqueous biphasic systems developed with deep eutectic solvents and polymer for the efficient extraction of pigments from beverages

Novel aqueous biphasic systems (ABSs) developed with benzyl-based quaternary ammonium salts-deep eutectic solvents (DESs) and polypropylene glycol (PPG) were herein proposed. The liquid-liquid equilibrium and the partitioning behavior of pigments in the systems were addressed. The results suggested that the shorter the carbon chain length of the DES, the easier to form two phases. The analysis of mixed samples showed that the selective separation was achieved in the ABSs, including 99.47% of tartrazine in the DES-rich phase and 98.47% of sudan III in the PPG-rich phase. Additionally, the systems were successfully applied to the extraction of pigments from the actual beverage samples with recoveries ranging from 93.43% to 102.15%. Furthermore, the study on the separation mechanism indicated that the hydrogen bonding played a significant role in the separation process. All the above results highlight the proposed DES/polymer-based ABSs have great advantages in selective and high-performance separation of pigments from beverages.

Aqueous two-phase system based on benzethonium chloride and sodium dihexyl sulfosuccinate for extraction and ICP-OES determination of heavy metals

An aqueous two-phase system (ATPS) based on benzethonium chloride (BztCl) and sodium dihexyl sulfosuccinate (NaDHSS) was proposed for the first time for liquid-liquid microextraction of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), and Pb(II) followed by ICP-OES determination. The mixture of cationic and anionic surfactants, BztCl and NaDHSS, showed liquid-liquid phase separation at the molar ratio of 1:1, and the total surfactant concentration of 0.01-0.2 mol L-1 forming ATPS that was investigated in the extraction process. The extraction efficiency for Cd(II), Co(II), Mn(II), Ni(II), and Pb(II) was nearly 100 %, and for Cu(II) - not lower than 88 % in the presence of 8-hydroxyquinoline as a complexing agent. The surfactant-rich phase containing analytes was subjected to back-extraction with 0.2 M HNO3 before ICP-OES measurements. The preconcentration in the proposed BztCl-NaDHSS-H2O ATPS for 30 s and the high degree of back-extraction, which was achieved in 1 min, significantly reduced the sample preparation time, matrix effects and provided low LODs in the range of 0.04-1.0 μg L-1, the preconcentration factor was 120. The analysis of a certified reference material sample of surface water and the real samples of tap, sea, and waste water verified the method accuracy.

Enantioselective liquid-liquid extraction of tryptophan enantiomers by a recyclable aqueous biphasic system based on stimuli-responsive polymers

The hydrophobic organic solvents/water biphasic system had been always used in the traditional enantioselective liquid-liquid extraction (ELLE). In recent years, aqueous biphasic systems (ABSs) are considered as a promising method used in the ELLE. In the present work, a recyclable ABS composed of a temperature-responsive polymer poly(MAH-β-CD-co-NIPAAm) (P_N-CD) and a pH-responsive polymer poly(AA-DMAEMA-BMA) (P_ADB) was employed in the enantioseparation of tryptophan enantiomers. The polymer P_N-CD acted as not only the phase-forming component but also the chiral selector, which can be recycled by changing the temperature. The polymer P_ADB can be used as the phase-forming component, which can also be recycled by adjusting the pH. The phase behaviors of this P_N-CD/P_ADB ABS had been studied. The influencing parameters were studied for this chiral separation process, including the polymer concentration, initial tryptophan concentration, extraction temperature, and system pH. The maximum separation factor (α) of 1.42 was obtained by one-step extraction under the optimal conditions. Meanwhile, the distribution coefficients of L-tryptophan (L-Trp) and D-tryptophan (D-Trp) were 2.79 and 1.96, respectively. This study develops a green and sustainable strategy for enantioseparation by using the ELLE.

Novel aqueous biphasic system based on ionic liquid for the simultaneous extraction of seven active pharmaceutical ingredients in aquatic environment

Nonsteroidal anti-inflammatory drugs and antibiotics are classes of active pharmaceutical ingredients (APIs), which are continuously contaminating the ecosystem through various anthropogenic activities. Because of their pseudo-persistence in the aquatic environment and their potentially chronic effects on aquatic life, it is important to closely monitor their concentrations in the aquatic environment using a sensitive analytical method. Sustainable aqueous biphasic systems (ABSs) composed of ionic liquids and biodegradable organic salt (sodium malate) were proposed. The phase diagrams of the systems were firstly determined, and [N₄₄₄₄]Cl-based ABS was selected for the simultaneous extraction and preconcentration of seven APIs. With the developed ABS, extraction efficiencies of APIs close to 100% were obtained. For the developed method, limits of detection (LODs) of 45, 65, 76, 14, 60, 48, and 51 ng L^-1 were obtained for indomethacin, ibuprofen, diclofenac, naproxen, ketoprofen, flurbiprofen, and chloramphenicol, respectively, providing from 1216- to 1238-fold improvement as compared with the analysis without preconcentration. From an economic and environmental point of view, we can predict the prospects and competitive position of the method developed.

Analysis of acetylcholinesterase inhibitors by extraction in choline saccharinate aqueous biphasic systems

Ionic liquid-based aqueous biphasic systems (IL-ABS) formed by ILs composed of ions of low toxicity, choline ([Chol]⁺) coupled with saccharinate ([Sac]^-) and acesulfamate ([Ace]^-), and inorganic salts with distinct water-structuring properties were employed for simultaneous extraction and concentration of acetylcholinesterase (AChE) inhibitors - galantamine (gal), N-desmethyl galantamine (des) and ungiminorine (ung). Comprehensive experiments aimed to assess the influence of salt and IL type and concentration, as well as the pH and temperature on the phase-forming ability and distribution of the target alkaloids between the two phases formed reveled that the IL anion and pH are the most important factors. At the optimal conditions found a quantitative recovery into the IL-rich phase of gal, des and ung was achieved in a single extractive step. These results were further used as a platform for the development of a simple and safer sample pretreatment method for analysis of the three analytes, followed by RP-HPLC/UV detection. The method showed satisfactory analytical performance, the latter allowing quantitative determination of these AChE inhibitors in pharmaceutical dosage form and in human urine.

Ionic liquids for the concomitant use in extremophiles lysis and extremozymes extraction

Ionic liquids have been successfully proposed to modify membrane permeability in cultures of a model extremophilic bacterium Thermus thermophilus HB27, which makes up the first time that aqueous solutions of these molten salts are applied in downstream stages of this kind of microorganisms. The presence of 1g/L of C10MIMCl entails a great solubilisation of cell biomass, thus allowing the release of intracellular and membrane-bound enzyme. The influence on the enzyme activity of two inorganic salts such as Na2CO3 and (NH4)2SO4, selected on the basis of their high salting out potential and biocompatibility with enzymes, respectively, was investigated. In parallel, their ability to trigger phase segregation was confirmed in the presence of the enzyme crude, leading to very high levels of enzyme extraction (96%). The validity of the strategy was confirmed by operating at bioreactor scale, and the main bioprocess parameters were obtained by modelling the experimental data.

Novel physico-biological treatment for the remediation of textile dyes-containing industrial effluents

In this work, a novel remediation strategy consisting of a sequential biological and physical process is proposed to remove dyes from a textile polluted effluent. The decolorization ability of Anoxybacillus flavithermus in an aqueous effluent containing two representative textile finishing dyes (Reactive Black 5 and Acid Black 48, as di-azo and antraquinone class, respectively) was proved. The decolorization efficiency for a mixture of both dyes reached almost 60% in less than 12h, which points out the suitability of the selected microorganism. In a sequential stage, an aqueous biphasic system consisting of non-ionic surfactants and a potassium-based organic salt, acting as the salting out agent, was investigated. The phase segregation potential of the selected salts was evaluated in the light of different thermodynamic models, and remediation levels higher than 99% were reached.