Sulphuric acid

Gallic acid, 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), sodium acetate, iron (II) sulphate heptahydrate, 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS), potassium peroxodisulfate, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), ascorbic acid, (−)catechin and caffeic acid were purchased from Sigma-Aldrich (Steinheim, Germany). Sulphuric acid, ethanol, hydrochloric acid, iron(III) chloride hexahydrate, acetic acid, sodium hydroxide and methanol were purchased from (Honeywell, Charlotte, NC, USA). Folin–Ciocalteu’s reagent was purchased from Carlo Erba (Chau. du Vexin, France). Citric acid and aluminum chloride were purchased from Merck Group (Darmstadt, Germany). Sodium citrate, sodium nitrite and vanillin were purchased from Semikem (Sarajevo, BiH). Potassium dihydrogen phosphate and di-potassium hydrogen phosphate were purchased from Kemika (Zagreb, Croatia). All standard solutions, electrolytes, and sample solutions were prepared with ultrapure water (0.05 μS cm⁻¹, Millipore Simplicity UV Water Purification System, Millipore, Burlington, MA, USA) using analytical-reagent grade chemicals.

Microbiological media (tryptone soy broth; TSB, tryptone soy agar; TSA, Muller Hinton agar; MHA, and Muller Hinton broth; MHB) were purchased from HiMedia, Mumbai, India. All chemicals and reagents were of analytical grade. Peptone and sodium chloride were purchased from Oxoid, Cheshire, UK. Hydrochloric acid, ethyl acetate and sulphuric acid were purchased from Honeywell™, North Carolina, USA. L- rhamnose was purchased from Sigma-Aldrich, Cairo, Egypt. Orcinol was obtained from SDFCL, Kolkata, India.

Methanol (CH₃OH) 99.8%, Nafion 117 solution, palladium (II) chloride (PdCl₂) 59–60%, tin(II) chloride (SnCl₂) 98%, and potassium bromide (KBr) ˃99.9% were purchased from Sigma Aldrich (St. Louis, MO, USA). Ethanol (C₂H₅OH) ˃99.9%, sulphuric acid (H₂SO₄) 95.0–97.0%, hydrochloric acid (HCl) 24–26%, and sodium hydroxide pellets (NaOH) 98% were supplied by Honeywell (Midrand, South Africa) and SRL Chemicals (Maharashtra, India). Potassium hydroxide pellets (KOH) 85% were obtained from Merck Chemicals (Germiston, South Africa). Flaxseed oil and wick were purchased from Checkers and Pick n Pay, respectively (Johannesburg, South Africa). All reagents were of analytical grade and used as received without further purification. De-ionized water was used throughout to prepare solutions.