Synthesis of aminothiophene derivative ligands and their complexes and application of electrochemical pesticide sensor

In this study, firstly, a ligand named 2-amino-6-ethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carbonitrile (ATL), which is an aminothiophene derivative, was synthesized according to the literature method. In the second stage, original ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes were synthesized. The chemical structures of the complexes were elucidated by spectroscopic methods such as FT-IR, UV-visible, and LC-MS mass analysis, as well as TGA-DTA analysis, magnetic susceptibility, and elemental analysis. Finally, electrochemical characterization of ATL and its complexes was performed. Additionally, sensor application for the pesticide carbofuran was carried out and studied. When its electrochemical behaviour was examined, it was seen that ATL exhibited an irreversible oxidation peak around 1,0 V. It was observed that ATL-Co(II), ATL-Cu(II) and ATL-Zn(II) complexes behaved similarly to ATL and exhibited an irreversible oxidation peak at the same potential. Carbofuran pesticide was added to the sensor medium using the standard addition method, and the changes in peak current and peak potential at different pesticide concentrations were recorded. The changes in peak current with different carbofuran concentrations constituted the data of the amperometric sensor application, the changes in the peak potential constituted the data of the voltammetric sensor application, and the obtained results were shown with graphics. Linear operating ranges, LOD and LOQ values were calculated for amperometric and voltammetric sensors studied using ATL, ATL-Co(II), ATL-Cu(II) and ATL-Zn(II) complexes.