Development of electrochemical sensor based on modified electrode for the determination of clopyralid and propham

In this study, electrochemical sensors based on modified electrodes were prepared for the determination of clopyralid and propham pesticides. The thesis study is composed of three main stages based on the types of modified electrode. At the first stage, a nanocomposite consisting of acid-activated multi-walled carbon nanotube and fumed silica (FS) was prepared to use in the determination of clopyralid and the nanocomposite prepared in this study used for the modification of glassy carbon electrode. A voltammetric method was developed for the determination of clopyralid using the modified electrode. A very low detection limit (0,8 nM) for clopyralid was obtained with the propose method. In the second stage of the thesis study, the carbon paste (CP) electrode was modified in a double-step procedure. In this frame, the CP was firstly modified with FS after that the electrode was remodified with a maghemite modified fumed silica nanocomposite which was synthesized for the first time in this study. The efficiency of the prepared electrode was examined in the determination of propham. At the last stage, polythiophene was synthesized electrochemically on the surface of the pencil graphite electrode and the synthesized polymer was over-oxidized. A voltammetric method for the determination of propham was developed using the obtained electrode. The performances of the modified electrodes prepared in this study were tested on real samples such as river water, wheat, sugar beet, potato, pesticide formulations and urine. The results showed that all the modified electrodes can be used safely in the determination of clopyralid and propham. Keywords: Sensor, Nanocomposite, Conducting polymer, Propham, Clopyralid.