Meta chloroperoxybenzoic acid

BA standards of histamine, putrescine, cadaverine, spermidine, spermine, 2-phenylethylamine, tyramine, isoamylamine and n-heptylamine (purity > 97%) were obtained from TCI Europe chemicals (Zwijndrecht, Belgium) and Across chemicals (Geel, Belgium). Tetraethyl orthosilicate (TEOS) (98%) from Alfa-Aesar (Kandel, Germany), 3-mercaptopropyltrimethoxysilane (MPTS) (95%) and (Diethylphosphatoethyl)triethoxysilane (DPETS) (95%) from ABCR (Karlsruhe, Germany), were used as precursors for the synthesis of functionalized silica. Bis[3-(silsequioxy)propyl] tetrasulfide was kindly donated by Sikemia (Montpellier, France). Triblock copolymer Pluronic P123 (Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)) from Aldrich (St. Louis, USA), and polyethylenglycol (PEG) 20,000 from Alfa-Aesar, were used as surfactants for the synthesis of silica by sol–gel route. Hydrochloric acid (37%), ethanol (> 99.8%), and nitric acid (65%) and dichloromethane (> 99.8%) from VWR (Fontenay sous Bois, France), and sulfuric acid (98%), Triphenylphosphine (99%), dioxane (99.8%), meta-chloroperoxybenzoic acid (99%) and diethylethoxymethylenemalonate (DEEMM), from Sigma-Aldrich (Steinheim, Germany), and ammonia (30%) from Carlo-Erba (Val de Reuil, France), were obtained.

Oleic acid (90%), 4-aminophenyl disulfide (98%), 2,2′-ethylendianiline (97%), trimethyl orthoformate (99%), 1,6-hexanediol (97%), 1-methylimidazole (99%), meta-chloroperoxybenzoic acid (77%), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (98%), dichloromethane (≥99%), ethyl acetate (≥99%), diethyl ether (≥99%), hexane (≥99%), methanol (≥99%), ethanol (96%), tetrahydrofuran (99%), tetrafluoroboric acid (57% in Et₂O), sulfuric acid (99%), NaCl (≥99%), NaHCO₃ (≥99%), Na₂SO₄ (≥99%) and Na₂SO₃ (≥99%) were purchased from Sigma-Aldrich Co., St. Louis, MO, USA, and all of them were used without further purification. All solvents used were of technical and analytical grade. Flash silica (High-purity grade, pore size 60 Å, 230–400 mesh particle size, 40–63 μm particle size, Sigma-Aldrich Co.) was used for purification. Thin-layer chromatography (TLC) was carried out by using silica gel on TLC plates (5 cm × 20 cm, silica gel matrix, fluorescent indicator, Sigma-Aldrich Co.)