Calcium nitrate ca no3 2 4h2o

The essential oil (EO) used in this study was P-EO. The peppermint plants (M. piperita) were harvested just before their full bloom, during summer (second week of July 2017), from an independent farm situated in southeast Romania. After being harvested, the peppermint plants were dried at room temperature, packed in paper bags, and stored in a cool and dry place. The P-EO was obtained by hydrodistillation from dried plants.
Hydroxyapatite Ca₁₀(PO₄)₆(OH)₂ solutions (HAp) were obtained by an adapted coprecipitation method [17 (link)] using as precursors calcium nitrate (Ca(NO₃)₂∙4H₂O, Sigma Aldrich, St. Louis, MO, USA), ammonium hydrogen phosphate ((NH₄)₂HPO₄; Wako Pure Chemical Industries Ltd., Richmond, VA, USA), ammonium hydroxide (NH₄OH, Wako Pure Chemical Industries Ltd., Richmond, VA, USA), and double-distilled water. The synthesis was done maintaining the molar ratio Ca:P = 1:67 [17 (link)]. The P-EO was added to the final HAp solution and the mixture was stirred for 24 h at room temperature. The final product, HAp-P, was analyzed by different techniques. An antimicrobial activity evaluation of the solutions was also conducted.

Chitosan (CTs) was acquired from Aldrich Chemical Company, Inc. (Milwaukee, WI, USA) and Hydroxyapatite (HAp) was produced according to a previously published technique [17 (link)].
Ammonium hydrogen phosphate (NH₄)₂HPO₄ (99%), calcium nitrate Ca(NO₃)₂·4H₂O (99%), lysine, Acetic acid (99%), and cadmium chloride (CaCl₂) were all purchased from Sigma Aldrich (Waltham, MA, USA) and utilized precisely as received, with no additional purification. Both runs utilized distilled water of high quality.
A Cd²⁺ and Zn²⁺ stock solution with a concentration of 1200 ppm (S0) was prepared.
Then, a series of diluted Cd²⁺ and Zn²⁺ solutions with concentrations of 300, 210, 170, 120, 100, 80, and 40 ppm were produced.

Calcium nitrate (Ca(NO₃)₂∙4H₂O, 99%, Sigma Aldrich), diammonium hydrogen phosphate (NH₄)₂HPO₄, DAP, 98%, Sigma Aldrich), 2-propanol (99.9%, Carlo Erba Reagents) and ethanol (99.2%, Carlo Erba Reagents) were used as received. As HAP standard we use hydroxyapatite nanoparticles purchased from Sigma Aldrich. Highly pure water (having a resistivity of 18 MΩ^.cm) produced by a Millipore Milli-Q UV system was used during all the experiments.

To obtain zinc-doped hydroxyapatite coated with dextran solutions by the sol-gel method we used calcium nitrate (Ca(NO₃)₂∙4H₂O, Sigma-Aldrich, St. Louis, MA, USA), zinc nitrate (Zn(NO₃)₂·6H₂O, Alfa Aesar, Karlsruhe, Germany; 99.99% purity), ammonium hydrogen phosphate ((NH₄)₂HPO₄), Alfa Aesar, Karlsruhe, Germany; 99.99% purity), triethanolamine (C₆H₁₅NO₃, Sigma-Aldrich, St. Louis, MA, USA ≥ 99.0% (GC) purity), dextran (H(C₆H₁₀O₅)_xOH, (MW ∼ 40,000), Merck, Kenilworth, NJ, USA) and ethanol (C₂H₅OH, Merck, Kenilworth, NJ, USA). Bi-distilled water was also used in the synthesis of dextran-coated zinc-doped hydroxyapatite.

Tetraethyl orthosilicate (TEOS) 99% (Sigma Aldrich, Steinheim, Germany), calcium nitrate (Ca (NO₃)₂.4H₂O) 98% (Sigma Aldrich, Steinheim, Germany), silver nitrate (Ag (NO₃)₂) 99% (Sigma Aldrich, Steinheim, Germany), and strontium nitrate (Sr (NO₃)₂) 99% (Sigma Aldrich, Steinheim, Germany), were used as silicon, calcium, silver, and strontium sources, respectively. Furthermore, ethyl acetate 99.8% (Sigma Aldrich, Steinheim Germany), cetyltrimethylammonium bromide (CTAB) 98% (Merck, Billerica, MA, USA), ammonium hydroxide 35% (VWR, Shanghai, China), distilled water, and absolute ethanol 99.8% were used. All chemicals used were of analytical grade.

The utilized pectin in this work was isolated from fresh O. ficus-indica cladodes that were collected in March 2021 from Oujda region, Morocco. HAp was synthetized in our laboratory. Calcium nitrate Ca(NO₃)₂.4H₂O (99.0%), ammonium hydrogen phosphate (NH₄)₂HPO₄ (99.0%), and dimethyl formamide were all purchased from Sigma-Aldrich, France, with high purity (greater than 99%), and were used as received. Purity deionized water was used in all runs.