Non-Enzymatic Electrochemical Sensors Based on ZnTPP Functionalized rGO Nanocomposites for Selective and Sensitive Catechol Detection Aiman Ishfaq Registration No:

Abstract

In this era of science and technology, factories setup and industrial advancement has expanded by leaps and bounds. The advancement though being in human favor has also caused devastating effects not only on human but also on his environment in the form of industrial pollution. In this regard leather, tanning, pharmaceuticals, food industries have garnered the limelight of being responsible for disposal of life threatening and highly toxic chemicals into the environment. One of them being dihydroxybenzenes, the detection of which has faced tremendous issues owing to the isomeric interference by them. This field of research focuses on the development of electrochemical sensors that could not only efficiently detect catechol (one of the isomer of dihydroxybenzene) but may also lead to its sensitive and selective detection without any kind of interference from other isomers of dihydroxybenzene. During the course of this research graphene oxide (GO) have been synthesized by modified Hummers and reduced graphene oxide (rGO) by chemical reduction method. Tetraphenylporphyrin (TPP) by Adler Longo method and zinc tetraphenylporphyrin (ZnTPP) by modified Adler Longo method. The composites of rGO-TPP and rGO-ZnTPP with 3 different ratios were employed for catechol detection. The composite formation was confirmed by FT-IR, UV-vis spectroscopy, SEM and EDS analysis. Among different composites rGO-ZnTPP (1:2) exhibited highest sensitivity towards catechol detection with a peak current of 126 μA. When subjected to a mixture of catechol and its competitive isomer hydroquinone the fabricated sensor rGO-ZnTPP (1:2)/GCE showed exceptional selectivity with two distinct peaks at varying potentials depicting the presence of two different species in the mixture. The peak to peak separation between hydroquinone and catechol came out to be 116 mV. The fabricated sensor rGO-ZnTPP/GCE also exhibited excellent limit of detection of 67 μM and exceptional sensitivity of 937.29 μAmM-1 cm-2