Tetracycline hydrochloride [C22H25N2O8Cl] (AR, 99 %), was provided from Sigma–Aldrich. Chemical properties of tetracycline hydrochloride are shown in Table 1 [2]. Sodium persulfate (Na2S2O8, 98 %) was provided from Sigma–Aldrich. All other chemicals were of analytical grade and were used without further purification. The water used in all experiments was purified by a Milli- Q system.
Table 1 Chemical properties of tetracycline hydrochloride
Molecule Formula Molecular weight (g/mol) Solubility (mol/L) pKa1 pKa2 pKa3
TC C22H24O8N2.HCl 480.9 0.041 3.2 ± 0.3 7.78 ± 0.05 9.6 ± 0.3