Adsorptive stripping voltammetric determination of nitroimidazole derivative on multiwalled carbon nanotube modified electrodes: influence of size and functionalization of nanotubes

摘要

1-Methyl-4-nitro-2-brominemethylimidazole (4-NimMeBr), was electrochemically reduced on mercury, glassy carbon and multiwalled carbon nanotubes (MWCNT) modified electrodes. 4-NimMeBr was adsorbed on the MWCNT modified electrode thus permitting the implementation of an adsorptive stripping voltammetric (ASV) method. We have used 4-NimMeBr as a prototype electroactive nitro compound to study the effect of both the size of the nanotubes and its functionalization by oxidation. The oxidized MWCNT forms better dispersions than the non-oxidized, producing electrode surface with higher density of MWCNT as was determined by electrochemical mapping using scanning electrochemical microscopy (SECM). Under the optimized conditions, the peak current was proportional to the concentration of 4-NimMeBr in the range of 10-6 mol L-1 to 10-4 mol L-1 with detection and quantification limits of 4.41×10-6 mol L-1 and 6.21×10-6 mol L-1, respectively. The sensibility of bare electrode was 0.01 μA per mmol L-1, which was lower than the value of 5.34 and 6.97 μA per mmol L-1 obtained using short and large oxidized MWCNT, respectively.