Electrochemical characteristics of composites based on novel asymmetric pillar[5]arene with carbon materials and their potential electrochemical applications

Electrochemical behavior of asymmetric pillar[5]arene (P5A) with one unsubstituted hydroquinone moiety and four ones with eight substituents bearing terminal amino groups was investigated for the first time on the surface of glassy carbon electrode (GCE) modified with various carbon nanomaterials (functionalized multi-walled carbon nanotubes (fMWCNTs), carbon black (CB), electrochemically reduced graphene oxide (ERGO)) by cyclic voltammetry. Quasi-reversible peak pair on voltammograms was attributed to the redox conversion of the hydroquinone moiety. P5A adsorbed at the modified GCE retained its ability to supramolecular interaction and demonstrated redox mediator properties. This effect was proved by the determination of L-tyrosine after its accumulation on the surface of GCE/CB/P5A sensor. The interaction between P5A and silver nitrate salt resulted in the formation of Ag nanoparticles. Morphology of P5A-Ag layers was assessed by transmission electron microscopy (TEM). Nanocomposite consisting of CB/P5A-Ag was also tested in nitrite-anion oxidation and demonstrated a reduction of the redox potential by up to 300 mV. Besides, a voltammetric GCE/CB/P5A-Ag sensor was used for chloride-anion determination in a concentration range from 50 µM to 0.1 mM.