Phosphate buffered saline ph 7

In terms of materials, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), chlorogenic acid (CGA), caffeic acid (CA), caffeine (CF), gallic acid (GA), 2,2-diphenyl-1-picrylhydrazyl (DPPH), formic acid, 3-(N-morpholino) propanesulfonic acid (MOPS), 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT), nitrilotriacetate disodium salt, nitrilotriacetate trisodium salt, phosphate-buffered saline (PBS) pH 7.0, phosphoric acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) and potassium thiosulfate were purchased from Sigma-Aldrich, Chemical Company (St. Louis, MO, USA). Ferric nitrate nonahydrate, sodium carbonate and Folin-Ciocalteu’s phenol reagent were obtained from the Merck-Millipore Company (Merck KGaA, Damstadt, Germany). Organic solvents, such as acetonitrile, were all of HPLC grade and all chemicals were highly pure and of analytical grade. Commercial instant coffee (regular and decaffeinated types) were purchased from a Tesco Supermarket in Chiang Mai Province, Thailand.

Graphene oxide (GO), 1 mg mL⁻¹, was synthesized in our laboratory39 . Na₂MoO₄ · H₂O, l-cysteine, and phosphate-buffered saline (PBS; pH 7.0) were purchased from Sigma Aldrich (P4417, USA). Horseradish peroxidase (HRP)-conjugated goat anti-mouse IgG (NC11430KR), and Blocker^TM BSA (10X) in PBS, were purchased from Thermo-Scientific. Alkaline phosphatase (ALP)-conjugated goat anti-mouse IgG (A3562), hydroquinone (HQ, H3660), hydrogen peroxide solution (216763), and (3-aminopropyl)triethoxysilane (APTES) were purchased from Sigma Aldrich. Ascorbic acid-2-phosphate (AAP) magnesium salt hydrate was obtained from Wako Pure Chemical Industries, Ltd (Product No. 013-12061, Osaka, Japan). Monoclonal PTH antibody, PTH antigen, and polyclonal PTH antibody were all sourced from Fitzgerald Industries. Deionized water (DIW, >18 MΩ cm), used to prepare all solutions in this study, was obtained from a water purification system.