Hydrochloric acid (hcl)

Bromophenol blue was obtained from Carlo Erba Reagents (Barcelona, Spain). For the synthesis of the AD, tert-butyl-[2-(3,5-dihydroxyphenyl)-2-hydroxyethyl]azanium sulphate (TBDA sulphate, molar mass 548.65 g mol⁻¹, Borg Pharmaceutical Industries, Borg El-Arab, Alexandria, Egypt), aniline (Al-Alamia for Chemical Industries, Egypt), sodium carbonate (ADWIC, Egypt) and sodium nitrite (SDFCL, India) were used. Ferric chloride hexahydrate, FeCl₃·6H₂O (Daejung Chemicals and Metals, South Korea), anhydrous sodium acetate (ADWIC, Egypt) and ethylene glycol (Honeywell International Inc., USA) were used to synthesize the SPIONs. Hydrochloric acid was purchased from Alpha Chemika (India) and ethyl alcohol was obtained from the International Company for Medical Industries (Egypt). All chemical reagents were of analytical grade and were used as received without any further purification. A BPB stock solution (1000 mg L⁻¹) was prepared by dissolving 50 mg of BPB in 50 mL of double distilled water. Working BPB solutions (10–100 mg L⁻¹) were prepared by diluting a stock BPB solution (1000 mg L⁻¹) with distilled water shortly before each experiment.

Bromocresol green (molecular formula: C₂₁H₁₄Br₄O₅S; CASN: 76-60-8; molar mass: 698.01 g mol⁻¹) was obtained from Carlo Erba Reagents (Barcelona, Spain). For the synthesis of the AD, thiamine hydrochloride (THC, molar mass of 337.27 g mol⁻¹, NODCAR, Egypt), also known as vitamin B1, tert-butyl-[2-(3,5-dihydroxyphenyl)2-hydroxyethyl]azanium sulphate (TBDA sulphate, molar mass of 548.65 g mol⁻¹, Borg Pharmaceutical Industries, Borg El-Arab, Alexandria, Egypt), sodium nitrite (SDFCL, India) and sodium carbonate (ADWIC, Egypt) were used. Ethylene glycol (Honeywell International Inc., USA), ferric chloride hexahydrate (FeCl₃·6H₂O, Daejung Chemicals and Metals, South Korea) and anhydrous sodium acetate (ADWIC, Egypt) were used for the solvothermal synthesis of SPIONs. Ethyl alcohol was obtained from the International Company for Medical Industries (Egypt), and hydrochloric acid was purchased from Alpha Chemika (India). All reagents were of analytical grade and were used without any further purification. Throughout the experimental work, deionized water was used for preparing aqueous solutions. An aqueous 0.01 M stock solution of BCG was prepared by dissolving an appropriate quantity of BCG in the least amount of ethanol and then completing the volume with deionized water. Working solutions were prepared by subsequent dilution of the stock solution with deionized water.