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

The electrodegradation of azithromycin was studied by its indirect oxidation using dimensionally stable Ti/RuO 2 anode as catalyst in the electrolyte containing methanol, 0.05 M NaHCO 3 , 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.