Hybrid cellulose-poly(4-vinylpyridine) adsorbents produced via ATRP and their application to target polyphenols in winemaking, olive oil production and almond processing residues

Fractionation of flavonols and anthocyanins in winemaking residues using molecularly imprinted cellulose‐synthetic hybrid particles with pyridyl active surface

“…For that, a low concentration of the monomers 4VP and EGDMA was used, and therefore, a weaker FTIR response of 4VP characteristic groups is expected (see refs. [12][13][14][15][16][17][18] dealing with different amounts of 4VP in the polymerization recipes).…”

“…135 m 2 g −1 estimated for the commercial resin DAX8) very high capabilities of the 4VP/EGDMA materials for adsorption of polyphenols are found as compared with several kinds of alternative adsorbents. [12][13][14][15][16][17][18] The functionalization of these materials with pyridyl groups is at the source of these outcomes, as discussed in the introduction section and also explored in the forthcoming analysis.…”

“…[1] Notably, adsorbents with pyridyl moieties present also a strong binding with phenolic compounds in different kinds of plant extracts and are being considered for valorization of these classes of bioactive compounds. [12][13][14][15][16][17][18] Actually, multivalent hydrogen bonding of the phenolic groups in polyphenols (e.g. quercetin and other related flavonoids) with the pyridyl groups in the polymer networks is possible at a relatively high binding strength.…”

“…At the end, the favorable interaction of the nucleophilic pyridyl group (weak base) with the phenolic hydroxyls (acidic groups) grounds the observed good performance of the related polymer networks for the retention of polyphenols, even at low extent of hydrophobic effects. [12][13][14][15][16][17][18] Targeting of specific compounds and/or functional groups with polymers arises from the particular selection of the functional moieties in the macromolecular chains. Besides this polymer functionalization level, an additional gain for materials tailoring can be conceived through the molecular imprinting technique that ideally leads to the formation of stereospecific cavities inside a polymer network.…”

Competitive Adsorption of Phenolic Acids, Secoiridoids, and Flavonoids in Quercetin Molecularly Imprinted Polymers and Application for Fractionation of Olive Leaf Extracts

“…Herein is reported the development of tailored polymer networks joining functionalization with 4-vinylpyridine (4VP) and molecular imprinting with quercetin as a template. 4VP was considered for functional monomer due to its special binding features that grounds the specific use for the development of advanced polymers in a wide range of applications (wastewater/industrial effluents treatment, enzyme/protein adsorption, electronics, biomedicine, or catalysis − ), including also adsorbents for plant extracts in view of the strong binding with phenolic compounds. − , The rationale for the selection of quercetin is based on its reference structure for many flavonoid molecules and because it is widely available (present in many plants) and is a less expensive molecule, therefore working as a kind of surrogate for flavonoids. Note that, in spite of a possible imperfect selectivity of MIPs and a likely high retention also observed with the correspondent NIPs (non-imprinted polymers) or functional commercial adsorbents, a positive impact of molecular imprinting was demonstrated, not only on specific binding sites formation but also on the improvement of the morphology and textural properties of the adsorbents. − …”