Application of anion‐exchange imidazolium silica for the multiphase dispersive extraction of phenolic acids

Abstract

This paper reports the application of a multiphase dispersive extraction method to the extraction, separation, and determination of the phenolic acids from Salicornia herbacea L. using silica-confined ionic liquids as sorbents. A suitable sorbent for phenolic acid extraction and separation was first identified based on the adsorption behavior of the phenolic acids on different silica-confined ionic liquids. The sample was then mixed with the optimized sorbent and solvent to achieve multiphase dispersive extraction. The sample/sorbent ratio was optimized using theoretical calculations from the adsorption isotherm and experiments. After transferring the supernatant to an empty cartridge, an SPE process was used to separate the three phenolic acids from the other interference. Through systematic optimization, the optimal conditions produced high recovery rates of protocatechuic acid (91.20%), caffeic acid (94.03%), and ferulic acid (91.33%). Overall, the proposed method is expected to have wide applicability.

Ionic liquid-modified silica gel as adsorbents for adsorption and separation of water-soluble phenolic acids from Salvia militiorrhiza Bunge

“…Besides the obvious strengthened adsorption peaks around 1717 cm À1 (stretching vibration of carbonyl groups on phenolic acids) and 1300-1500 cm À1 (bending vibration of alkyl groups on phenolic acids), it can be seen that the adsorption of phenolic acids onto the ionic liquid-modified silica results in the disappearance of the band at 851 cm À1 , which is attributed to P-F stretching vibration. The loss of anion (PF 6 À ) can be ascribed to the anion-exchange interaction between ionic liquid-modified silica and phenolic acids molecules in water, which is consistent with results in the literature [12]. The skeleton stretching vibration absorption peak of imidazole ring at 1576 cm À1 shows red shift after adsorption, which indicates that the vibration of imidazole ring was restricted at some extent and the ring makes an obvious contribution to the adsorption process of phenolic acids.…”

“…[12,22]). The interactions between target phenolic acids and ionic liquids mainly include hydrogen bonding interaction [8], electrostatic attraction, conjugate action and anion exchange [12]. So, intermolecular Hbond force of various anions will also affect the adsorption performance besides their hydrophobicity.…”

“…As one and only salt among five constituents, sodium danshensu has the highest water-solubility and firstly eluted on reverse-phase column. Nevertheless, the ionic liquid-modified silica based on N-methylimidazolium can also display a strong Hbonding and anion-exchange mechanism [12]. Compared with protocatechuic aldehyde, sodium danshensu has more phenolic hydroxyl groups, which are the H-bonding interaction sites with ILs functional groups.…”

“…Considering structural diversity and propertical difference of the active constituents from herbs, a wider variety of ionic liquid-modified silica gels are needed to be urgently developed. As a new adsorbent material, ionic liquidmodified silica gel combined with the advantage of ILs and solid supports is usually applied in analytical fields, including the separation of organic compounds [9], metal ions in the environment [10], and phenolic compounds from water [11,12]. However, there is no application reported about the preparative separation for natural salvianolic acids up to now.…”

Investigation of 1-Dodecylimidazolinm Modified Filter Papers as a Thin-Film Microextraction Phase for the Preconcentration of Bisphenol A from Plant Oil Samples

“…Moreover, a surface confined ionic liquid phase, which combines the advantages of ionic liquids with those of support materials, has been successfully used in the field of separation. [33][34][35] BPA possesses amphiphilic properties, such as hydrophilic hydroxyl groups (pKa = 10.29) and hydrophobic aromatic groups (log Ko/w = 3.641). 36,37 Generally, ionic liquids modified materials are especially interesting for those analytes with acid groups and aromatic rings in their chemical structures.…”