Degradation of azithromycin using Ti/RuO2 anode as catalyst followed by DPV, HPLC-UV and MS analysis

Abstract

The electrodegradation of azithromycin was studied by its indirect oxidation using dimensionally stable Ti/RuO2 anode as catalyst in the electrolyte containing methanol, 0.05 M NaHCO3, sodium chloride and deionized water. The optimal conditions for galvanostatic electrodegradation for the azithromycin concentration of 0.472 mg cm(-3) were found to be NaCl concentration of 7 mg cm(-3) and the applied current of 300 mA. The differential pulse voltammetry using glassy carbon electrode was performed for the first time in the above-mentioned content of electrolyte for the nine concentration of azithromycin (0.075-0.675 mg cm(-3)) giving the limits of azithromycin detection and of quantification as: LOD 0.044 mg cm(-3) and LOQ 0.145 mg cm(-3). The calibration curve was constructed enabling the electrolyte analysis during its electrodegradation process. The electrolyte was analyzed by high-performance liquid chromatography and electrospray ionization time-of-flight mass spectrometry. The electrooxidation products were identified and after 180 min there was no azithromycin in the electrolyte while TOC analysis showed that 79% of azithromycin was mineralized. The proposed degradation scheme is presented.