Deep eutectic solvent-mediated synthesis of ZnCo 2 O 4 /MWCNT-COOH: Investigation of electrocatalytic activity for gatifloxacin detection

The overuse of gatifloxacin seriously pollutes the environment and cause potential harm to our health. Hence, it is imperative to develop a rapid and sensitive method for gatifloxacin determination. Herein, an efficient electrocatalyst was designed for the voltammetric determination of gatifloxacin based on carboxylated multiwalled carbon nanotubes warped ZnCo 2 O 4 nanoparticles (ZnCo 2 O 4 /MWCNT-COOH). The ZnCo 2 O 4 nanoparticles were synthesized by a green deep eutectic solvent-mediated ion-thermal route, and further composited with MWCNTsCOOH. The ZnCo 2 O 4 / MWCNT-COOH combined the catalytic activity of ZnCo 2 O 4 with the high electrical conductivity of MWCNT-COOH, aiming to improve the electrochemical sensing performance toward gatifloxacin. The synergistic interactions between ZnCo 2 O 4 and MWCNT-COOH endowed the ZnCo 2 O 4 /MWCNT-COOH with extraordinary catalytic activity for gatifloxacin oxidation. Consequently, the ZnCo 2 O 4 /MWCNT-COOH displayed a wide linear response range (0.01 -10 mu M) for detecting gatifloxacin, with a high sensitivity (29.64 mu A mu M-1 cm-2 ) and low detection limit (2.0 nM). The ZnCo 2 O 4 /MWCNT-COOH showed robust voltammetric responses against potential interfering species, and maintained highly stable responses for at least two weeks. Moreover, the ZnCo 2 O 4 /MWCNT-COOH/GCE was successfully used to detect gatifloxacin in water samples with satisfactory recoveries (97.22- 104.5 %). Together with its low cost, environment friendly and rapid response, the ZnCo 2 O 4 / MWCNT-COOH shows promising prospects in trace detection of gatifloxacin.