[c] 1IntroductionThee xistence of aw ide varietyo fe merging micropollutants in the environment and its effecto nt he wildlife and the humanh ealth has been demonstrated by several studies,especiallyf or some pharmaceutical agents,s uch as antibiotics. Due to the potential impacto fa ntibiotics on non-targeted species,i tb ecame am ajor concern to develop ac ost-effective,h ighly sensitive and easyt oo perate analytical methodf or real-timem onitoring of the level of the pharmaceutical agents.Among the antibiotics,M TZ or 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole belongs to the nitroimidazole group of pharmaceutical agents;i ti se mployed in both human and veterinary medicine to treatd iseases caused by anaerobic bacteria and protozoa [1].H owever, it was found that this drugp ossesses carcinogenic,m utagenic and toxic properties.M TZ metabolites are also carcinogenic and mutagenic in some animal species,b ecause they retain the original nitroimidazoler ing [2].A lthough this compound has been prohibited in food production in many countries,i ti sstill used in aquaculture [3,4].M TZ is not only very soluble in water,b ut it also has photo and hydrolytic stability [5,6],s oi tc an accumulate in the aquatice nvironment [7,8].H ence, this drug can have as ignificant impacto nn on-target aquatic organisms and may lead to the formation of bacterials trains resistant to its effects [9,10] [18][19][20][21][22].M oreover, the assay method for metronidazole recommended by Pharmacopoeia is based on HPLC using UV detection at wavelengtho f318 nm [25].Electrochemical analysisi so ne of the most attractive methods of quantification for different chemical agents, due to its simplicity,h igh sensitivity,f ast response and relatively low cost [23][24].T herefore,d ifferent chemically modified electrodes have been developed for sensing MTZq uantitatively,ass hown in table 1 [18][19][20][21][22].CPE is am ixture of an electrically conducting graphite powder and ap asting liquid. It has been widely usedi n electroanalytical chemistry as aw orking electrode.T his is because it possesses variousa dvantages,e .g;awide potential range,s imple and fast preparation, convenient surAbstract:A ne lectrochemical sensor for metronidazole (MTZ)w as built via the surface modification of ac arbon paste electrode( CPE) by afilm obtainedthrough electropolymerization of a-cyclodextrin( CPE a-CD ). TheC PE a-CD was characterized by cyclic voltammetry (CV)a nd atomic force microscopy (AFM), by both techniques was demonstrated that the polymerf ilm is coating the electrode surface.T he electroreduction behaviour of MTZi nH ClO 4 media as as upporting electrolyte was studied by differential-pulse voltammetric (DPV)t echnique.T he DPV electrochemical process was observed to be diffusionc ontrolled and irreversible.U nder optimal conditions,t he peak current was proportional to MTZ concentration in the rangeo f0 .5 to 103.0 mMw ith ad etection limit of 0.28 AE 0.02 mM. Them ethodw as successfully applied to quantify of MTZi np harmaceutical formul...
