3 mercaptopropyltrimethoxysilane

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.

Chloroacetic acid (ClAAc, pure), alkenes: 1-decence (C10, >97%), 1-tetradecene (C14, >97%); chloroform (purum, >99.5%), chloroform-d (>99.8 atom %D, with 0.05% (v/v) tetramethylsilane), dimethyl sulfoxide (DMSO, >99.5%), 7-diethylamino-3-(4-maleimidophenyl)-4-methylcoumarin (CPM, >90%), and fluorescein diacetate 5-maleimide (FDM, for fluorescence) were acquired from Sigma-Aldrich (St. Louis, MO, USA); 3-mercaptopropyltrimethoxysilane (McPTMS, >95%) and dibutyltin dilaurate (DBTL) were acquired from ABCR (Karlsruhe, Germany); 1-propanol (PrOH, Baker analysed >99%) was acquired from Fischer Scientific (Hampton, NH, USA). White, commercially available plain-weave cotton fabrics were used without any further treatment; 70 mm diameter Whatman Schleicher & Schuell ashless 589/2 white ribbon filter paper (Maidstone, UK) was used as the paper substrate without any further treatment.