Phosphoric acid

Amiloride hydrochloride and (±)-propranolol hydrochloride were purchased from Sigma-Aldrich (St. Louis, MI, USA). HPLC-grade methanol used for the preparation of stock and working solutions and the HPLC grade acetonitrile used for the mobile phase was provided by Romil (Cambridge, England). For the preparation of the extraction buffer solution, potassium dihydrogen phosphate (>99%) obtained from Merck (Darmstad, Germany) and phosphoric acid (85%) supplied by Panreac (Barcelona, Spain) were used. Ultrapure analytical water was obtained from a Milli-Q Element A10 system (Millipore, Milford, CT, USA). α-cyano-4-hydroxycinnamic acid (CHCA) and DAN (1,5-Diaminonaphthalene) from Sigma-Aldrich and DHB (2,5-Dihydroxybenzoic acid) supplied by Acros Organics (Geel, Belgium) were used as ionizable matrices for MALDI-IMS experiments. Standard stock solutions of 1000 mg/L were prepared in methanol for each analyte separately. With those solutions, 50 mg/L working solutions in methanol were prepared.

Sodium hypochlorite (10%), hydrogen peroxide (30%), sulfuric acid (50%), phosphoric acid (25%), hydrochloric acid (25%), ultra-pure ethanol (96%) and glacial acetic acid (99.5%) were purchased from PanReac AppliChem (Barcelona, Spain). Graphite flakes (99%), pepsin, N-[3-(dimethylamino)-propyl]-N’-ethylcarbodiimide hydrochloride (EDC) (98%), N-hydroxysuccinimide (NHS) (98%), ascorbic acid (99%), sodium chloride (99%), triton X-100, potassium permanganate (99%) and formaldehyde (36%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Dulbecco’s modified eagle’s medium (DMEM) and fetal bovine serum (FBS) were obtained from Biowest (Nuaillé, France). Penicillin/streptomycin (P/S) was purchased from Lonza (Basel, Switzerland). Hoechst 33342, Alexa Fluor 594 Phalloidin, LDH and alamar blue assay kits were purchased from Thermo Fisher Scientific (Waltham, MA, USA). Vero (ATCC^® CCL-81), HaCat (ATCC^® CCL-2404) and HFF-1 (ATCC^® SCRC-1041) cells were obtained from ATCC (St. Cloud, MN, USA).

APPH (2,2-azobis 2-amidopropane dihydrochloride), gallic acid, sodium fluorescein and trolox were purchased from Sigma. Acetonitrile, ammonium phosphate monobasic, chlorohydric acid, ethanol, Folin-Ciocalteu reagent, phosphate salts (NaH2PO4·2H2O and Na2HPO4·12H2O), phosphoric acid, potassium chloride, sodium acetate and sodium carbonate were obtained from Panreac. HPLC standards catechin, delphinidin, epicatechin, gallic acid, malvidin and quercetin were bought from Extrasynthese, except for kaempferol which was purchased from TCI. A Millipore unit was used to purify the water used as solvent.

Tert-butylhydroperoxide (t-BOOH), (−)-epicatechin (EC, >95% of purity), Glutathione reductase (GR), reduced glutathione (GSH) and oxidized glutathione, dichlorofluorescin (DCFH), o-phthaldialdehyde (OPT), nicotine adenine dinucleotide phosphate reduced salt (NADPH), gentamicin, penicillin G and streptomycin were purchased from Sigma-Aldrich Chemical (Madrid, Spain). Bradford reagent was from BioRad Laboratories S.A (Madrid, Spain). Methanol of HPLC grade, dimethyl sulfoxide (DMSO), light petroleum and phosphoric acid of analytical grade were purchased by Panreac (Barcelona, Spain). DMEM culture media and foetal bovine serum (FBS) were from Cultek (Madrid, Spain). All other reagents were of analytical quality.

l-aspartic acid, phosphoric acid (85%), and hydrochloric acid (HCl, 35%) were obtained from Panreac. 1,4-Diaminobutane (DAB, 99%), imidazole, 4-dodecylbenzenesulfonic acid (DBSA), 3,4-ethilendioxitiophene (EDOT, 97%), hydroxmethyl-3,4-ethylenedioxythiophene (HMeDOT, 95%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Dimethyl sulfoxide (DMSO, dried, max. 0.025% H₂O), methanol (MeOH, 99.9%), potassium chloride, mesitylene, and sulfolane were acquired from Merck (Darmstadt, Germany).