3.1. Chemicals

Sigma-Aldrich provided the high-molecular-weight CS (MW = 310–375 kDa; deacetylation degree = 75%), gallic acid ((OH)₃C₆H₂CO₂H, purity ≥ 98%), catechin (C₁₅H₁₄O₆, purity ≥ 98%), vanillin (4-(HO)C₆H₃-3-(OCH₃)CHO, purity ≥ 97%), and silica gel 60G (230–400 mesh, 0.04–0.06 mm) (San Luis, MO, USA). Ethyl alcohol P.A. (C₂H₆O, purity 98%), sulfuric acid P.A./ACS (H₂SO₄, purity 95–98%), phosphoric acid P.A. (H₃PO₄, purity 85%), hydrochloric acid P.A./ACS (HCl, purity 37%), dichloromethane P.A. (CH₂Cl₂, purity 99%), ethyl acetate P.A. (C₄H₈O₂, purity 99%), PEG (PEG 400, H(OCH₂CH₂)_nOH), and sodium carbonate (Na₂CO₃) were purchased from NEON (Suzano, SP, Brazil). Dinamica (Sao Paulo, Brazil) supplied the acetic acid P.A. (CH₃CO₂H, purity 99.8%). Lactic acid P.A. (C₃H₆O₃, purity 85%) was purchased from Anidrol (Diadema, SP, Brazil). Silica slabs 60 F₂₅₄ (0.015–0.040 mm) were purchased from Supelco (Bellefonte, PA, USA). HPLC grade acetonitrile (CH₃CN, purity ≥ 99.9%) and Folin-Ciocalteu reagent were from Merck (Darmstadt, HE, Germany). J.T. Baker provided HPLC grade methanol (CH₃OH, purity ≥ 99.9%) (Phillipsburg, NJ, USA). All solutions were made with 18.2 mΩ·cm ultrapure water obtained from a Merck Mili-Q Reference System (Darmstadt, HE, Germany). All of the chemical reagents utilized in this study were of analytical grade.