Electrode material Techniques Interference Detection Limit (molL-1) References SWNT/Ppy,Surf.cov.bend SWV AA 5.00 x 10-6 [60] MWCNT/B-CD modified GCE SWV AA 6.70 x 10-6 [61] Fe3O4/rGO/GO SWV AA 1.20 x 10-7 [62] GCE/MWCNT-NiO SWV AA 7.99 x 10-12 This work GCE/MWCNT-ZnO SWV AA 3.74 x 10-7 This work GCE/MWCNT-Fe3O4 SWV AA 1.39 x 10-6 This work

Table 1: Impedance data obtained for the bare GCE and the modified electrodes in 5 mM Fe(CN)6]4−/[Fe(CN)6]3− solution at 0.2 V (vs. Ag/AgCl saturated KCl). All values were obtained from the fitted impedance spectra. The values in parentheses are percent errors of data fitting.