Electrochemical investigations of a series of 2-(4-(1-isonicotinoyl-5-aryl-4,5-dihydro-1H-pyrazol-3- yl)phenoxy)-N-arylacetamides at modified glassy carbon electrode

A series of 2-(4-(1-isonicotinoyl-5-aryl-4,5-dihydro-1 H -pyrazol-3-yl)phenoxy)- N -arylacetamides has been synthesized in appreciable yields. The quantitative determination and redox behavior of the synthesized compounds was estimated by electrochemical technique using cyclic voltammetry (CV). For this purpose highly sensitive and stable zinc oxide (ZnO)- multi walled carbon nanotubes (MWCNTs) composite film modified glassy carbon electrode (GCE) (ZnO-MWCNTs/GCE) was used as a working electrode. The increase in effective surface area of modified GCE from that of unembellished GCE of 0.0314 cm 2 upto 0.081 cm 2 resulted in better electrocatalytic activity in terms of responses of the compounds under investigation. The composite film modified GCE resulted into an excellent sensor for the reported compounds in terms of low potential detection, a low detection limit, fast and clear response. Moreover the effect of pH, varying scan rates, solvents, electrolytes, concentration, and substituents (in terms of Hammett equation) have also been analyzed on the CV responses of the modified GCE. The incorporation of ZnO nanoparticles with multi walled carbon nanotubes (MWCNTs) greatly increases the voltammetric peak current and electrochemical reactivity of the compounds. The electrochemical sensor shows excellent analytical performance and exhibited a wide detection range from 0.0001 M to 0.0003 M. The studies delineated the diffusion-controlled and irreversible behavior of electrocatalytic reaction for all the compounds under investigation.