Electrode modification based on “click electrochemistry” between terminal-alkynyl substituted cobalt phthalocyanine and 4-azidoaniline

Abstract

A new electrochemical sensor electrode was constructed with a new electrode modification technique, “click electrochemistry” (CEC) based on a functional cobalt phthalocyanine. In this newly constructed modified electrode (GCE/PANI-N3/TA-CoPc (CEC)), a terminal-alkynyl (TA) substituted cobalt phthalocyanine (CoPc-TA) was electrochemically bonded to the azido end of electro-polymerized 4-azidoaniline (PANI-N3), which was electropolymerized on the GCE electrochemically previously. GCE/PANI-N3/TA-CoPc (CEC) electrode was characterized with voltammetric, electrochemical impedance spectroscopy (EIS), UV–vis spectroscopy, and scanning electron microscopy (SEM) techniques. GCE/PANI-N3/TA-CoPc electrode gave three redox couples assigned to the CoPc and PANI in nonaqueous and aqueous electrolyte systems, which is a desired factor for the application of a modified electrode in various electrochemical applications such as electrocatalytic and electrosensing fields. Pesticide sensing responses of GCE/PANI-N3/TA-CoPc (CEC) electrode were tested with SWV method for usability as an electrochemical pesticide sensor for eserine. Basic sensor parameters, calibration lines, and detection limits (LOD) of GCE/PANI-N3/TA-CoPc (CEC) electrode were derived from SWV responses of the electrode. Amperometric sensing analyses of SVW responses of the electrode give a linear range between 1.56×10−7 and 2.45×10−6moldm−3 eserine with a sensitivity of 1.15Adm3mol−3 and LOD of 1.75×10−7moldm−3.