Optimization of the gallic acid extraction using ionic-liquid-based aqueous two-phase systems

Extraction and Recovery of Rutin from Acerola Waste using Alcohol-Salt-Based Aqueous Two-Phase Systems

“…In the ATPS formed by K 2 HPO 4 and K 2 HPO 4 /KH 2 PO 4 the improved migration for the alcohol-rich phase with the increase on the initial rutin content can be a main result of solute-solute interactions such as · · · interactions (non-covalent interactions between the aromatic rings) and improved hydrogen-bonding ability between the hydroxyl groups. This pattern was already observed by Cláudio and co-workers (40) with the partitioning of vanillin in ATPS composed of ionic liquids and salts. Furthermore, Tavagnacco and co-workers (43) have already demonstrated the presence of · · · interactions in aromatic solutes when dissolved in aqueous media using molecular dynamics simulations.…”

“…These differences in the phases' polarities, coupled to the charged or non-charged nature of rutin, control the preferential migration for a given phase. Indeed, this trend was already observed in the partition coefficients of gallic acid using ATPS formed by ionic liquids and different inorganic salts (40). In this work (40), it was observed that the neutral and less hydrophilic form of gallic acid present in the acidic media, is more easily extracted into the most hydrophobic ionic-liquid-rich phase.…”

“…In this work (40), it was observed that the neutral and less hydrophilic form of gallic acid present in the acidic media, is more easily extracted into the most hydrophobic ionic-liquid-rich phase. On the other hand, gallate, the charged conjugate base of gallic acid present in neutral or alkaline pH solutions, preferentially migrated into the charged salt-rich phase (40).…”

Separation and concentration of hydroxycinnamic acids in alkaline hydrolyzate from rice straw by nanofiltration

“…The pK a of phenolic acids varied in the range of 4 and 5 (see Table 2), indicating that in the pH range tested, pH variation would significantly influence the degree of dissociation. During NF process, sieving mechanism and Donnan exclusion are two main mechanisms for molecular separation [16,17]. At pH 3.23, 95.62% of vanillic acid, 95.63% of ferulic acid and 95-96% of p-coumaric acid were undissociated based on the calculation using pK a values (Henderson-Hasselbalch equation), indicating that the sieving mechanism would be dominant during NF separation.…”

Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

“…effective method for the extraction of various compounds, such as aesculin and aesculetin from Cortex fraxini [17], piperine from white pepper [18], ginsenosides from ginseng root [19], alkaloids from Catharanthus roseus [20], biphenyl cyclooctene lignans from Schisandra chinensis Baill [21], magnolol and honokiol from Magnoliae officinalis cortex [22]. Aqueous biphasic systems based on ionic liquids (IL-ABS) were proposed in 2003 by Rogers [23], and have been developed to extract and isolate several bioactive compounds, such as anthraquinones [24], gallic acid [25], puerarin [26], and alkaloids [27].` The analysis and identification of the flavonoids in A. venetum leaves using liquid chromatography-tandem mass spectrometry (LC-MS/MS) are well reported in the literature [28][29][30]. The present article reports the extraction of flavonoids from A. venetum into IL aqueous solution by the IL-UAE method, with further application of IL-ABS for preconcentration and purification of the flavonoids.…”