For the boric acid standard solution preparation, 1 mg, 1.5 mg, 2.5 mg, 3.5 mg, 5 mg, 7.5 mg, and 10 mg of weighed boric acid were dissolved in 0.5 mL of D2O.
For the borax standard solution preparation, 1.5 mg, 2.5 mg, 3.5 mg, 5 mg, 7.5 mg, and 10 mg of weighed borax were dissolved in 0.5 mL of D2O. All relevant standard solutions in the experiments of this paper were prepared without using pH buffer solutions.
11B NMR solutions of borax were prepared at various pHs: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12. A weighed amount of borax was dissolved in a D2O solution, After borax had been completely dissolved, the pH of the solution was adjusted with NaOH or acetic acid. The pH detection of borax aqueous solution was carried out using pH precision test strips. For the 11B NMR study of borax solutions at various temperatures, 10 mg of borax was dissolved in 0.5 mL of D2O. The temperature control switch of the NMR spectrometer was turned on and an 11B NMR experiment was conducted after stabilizing at the target temperature.
For the borax standard solution preparation, 1.5 mg, 2.5 mg, 3.5 mg, 5 mg, 7.5 mg, and 10 mg of weighed borax were dissolved in 0.5 mL of D2O. All relevant standard solutions in the experiments of this paper were prepared without using pH buffer solutions.
11B NMR solutions of borax were prepared at various pHs: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12. A weighed amount of borax was dissolved in a D2O solution, After borax had been completely dissolved, the pH of the solution was adjusted with NaOH or acetic acid. The pH detection of borax aqueous solution was carried out using pH precision test strips. For the 11B NMR study of borax solutions at various temperatures, 10 mg of borax was dissolved in 0.5 mL of D2O. The temperature control switch of the NMR spectrometer was turned on and an 11B NMR experiment was conducted after stabilizing at the target temperature.
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