Reduced graphene oxide/iron(II) porphyrazine hybrids on glassy carbon electrode for amperometric detection of NADH and L-cysteine

Abstract

The microwave-assisted macrocyclization reaction of 2,3-bis[2-(morpholin-4-yl)ethylsulfanyl]-(2Z)-butene-1,4-dinitrile led to novel symmetrical iron(II) sulfanyl porphyrazine. Novel macrocycle was carefully characterized using UV–vis, MS, NMR, and FTIR. The electrochemical and spectroelectrochemical measurements were performed to assess electrochemical properties of sulfanyl porphyrazine with 2-(4-morpholinyl)ethyl moieties in its periphery. Four redox processes were observed in voltammetric studies. However, no oxidation of iron cation was noticed in the UV–vis spectra at applied overpotentials. The catalytic study of porphyrazine performed in the dark with the use of DPBF and proper oxygen atom donor, resulted in a decrease of DPBF absorbance due to the formation of its oxidized form. Next, sulfanyl porphyrazine was deposited on graphene oxide sheets and reduced electrochemically to obtain stable hybrid material for the modification of glassy carbon electrode surface ready for amperometric sensing purposes. Electrooxidation of NADH and L-cysteine were studied indicating electrocatalytic activity of novel material towards 1 mM solutions of each analyte. Therefore, the reduced graphene oxide/iron(II) porphyrazine hybrids can be considered as an attractive material for modification of glassy carbon electrode surface. Their application can be found in the design of electrochemical sensors and biosensors or electrochemical catalysts for the electrochemical oxidation processes of various organic compounds, including bioactive components.