Potassium dihydrogen phosphate

Acetic acid (99.5%), aluminum chloride hexahydrate, copper(II) chloride dihydrate, disodium hydrogen phosphate dihydrate, 96% ethanol, 36% hydrochloric acid, iron(III) chloride hexahydrate, methanol, phosphoric acid, potassium persulfate, potassium dihydrogen phosphate, potassium hexacyanoferrate(III), sodium acetate anhydrous, sodium carbonate anhydrous, sodium hydroxide, sodium nitrite, and trichloroAcetic acid were purchased from Chempur, Poland. Neocuproine was delivered by J&K Scientific, Germany. Folin–Ciocalteu reagent, acetonitrile, iron(II) sulfate heptahydrate, gallic acid were supplied by Merck, Germany, whereas rutin trihydrate by Roth, Germany. ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), TPTZ (2,4,6-tris(2-pyridyl)-s-triazine), Trolox (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid), caffeine were purchased from Sigma-Aldrich, USA. All the chemicals were of analytical grade.

Cadmium oxide (CdO; 99.5%), oleic acid (OA; technical grade 90%), octadecene (ODE; technical grade 90%), zinc acetate (Zn(Ac)₂; 99.99%), sulfur (S; 99.998%), d-penicillamine (DPA; 99%) and 3-mercaptopropionic acid (3-MPA; 99%) were purchased from Sigma-Aldrich (Saint Louis, MO, USA). Acetic acid (Ac, 99.7%), ethanol (99.8%), hexane (95%), hydrochloric acid (98.5%), sodium hydroxide (98.8%), potassium dihydrogen phosphate and disodium hydrogen phosphate were purchased from Chempur (Piekary Śląskie, Poland). All chemicals were used without further purification.

Medium-molecular-weight CS 80/50 (degree of deacetylation: 77.6–82.5%, viscosity of 1% solution in 1% acetic acid: 31–70 mPa·s, molecular weight: 80–200 kDa) was obtained from Heppe Medical CS GmbH (Haale, Germany). Low-methoxy amidated PC with low- (a type CF 010, degree of esterification 34%, degree of amidation 17%, pH 4.2 for 2.5% solution in distilled water at 20 °C) and high-calcium reactivity (a type CF 020, degree of esterification 31%, degree of amidation 19%, pH 4.1 for 2.5% solution in distilled water at 20 °C) were kindly gifted by Herbstreith & Fox and GmbH & Co. KG (Neuenbürg, Germany). Potassium dihydrogen phosphate, sodium chloride, calcium chloride dihydrate, and 85% lactic acid were purchased from Chempur (Piekary Śląskie, Poland). Glycerol was obtained from Fagron (Kraków, Poland).
SSS composed of Potassium dihydrogen phosphate (1.63 mg/mL), sodium chloride (2.32 mg/mL), and calcium chloride dihydrate (0.22 mg/mL) with pH 6.2 adjusted by disodium hydrogen phosphate addition (according to Nair et al. with modification [25 (link)]) was used for the research analyses.