Exfoliation of graphite rods via pulses of current for graphene synthesis: Sensitive detection of 8-hydroxy-2'-deoxyguanosine

Florina Pogacean; Maria Coros; Lidia Magerusan; Valentin Mirel; Alexandru Turza; Gabriel Katona; Raluca-Ioana Stefan-van Staden; Stela Pruneanu

doi:10.1016/j.talanta.2018.12.051

Exfoliation of graphite rods via pulses of current for graphene synthesis: Sensitive detection of 8-hydroxy-2'-deoxyguanosine

Talanta. 2019 May 1:196:182-190. doi: 10.1016/j.talanta.2018.12.051. Epub 2018 Dec 18.

Authors

Florina Pogacean¹, Maria Coros¹, Lidia Magerusan¹, Valentin Mirel¹, Alexandru Turza¹, Gabriel Katona², Raluca-Ioana Stefan-van Staden³, Stela Pruneanu⁴

Affiliations

¹ National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca, Romania.
² Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany Janos 11, Cluj-Napoca, Romania.
³ Laboratory of Electrochemistry and PATLAB, National Institute of Research for Electrochemistry and Condensed Matter, 202 Splaiul Independentei Street, 060021 Bucharest-6, Romania; Faculty of Applied Chemistry and Material Science, Politehnica University of Bucharest, Bucharest, Romania.
⁴ National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca, Romania. Electronic address: stela.pruneanu@itim-cj.ro.

PMID: 30683349
DOI: 10.1016/j.talanta.2018.12.051

Abstract

In this paper we present for the first time a novel method for graphene-based materials synthesis, by exfoliation of graphite rods via pulses of current (pulse duration of 2.5 s; pause between two pulses of 0.8 s). The method has several advantages over the classical one (d.c. current exfoliation) such as the prevention of the electrolyte over-heating, the generation of less amount of graphitic material into the final sample, the increase of the synthesis yield, and the excellent reproducibility in sample quality when the synthesis parameters are preserved. The first material (EGr-A) was obtained in strong acidic solution made by a mixture of H₂SO₄ and HNO₃ (3:1 ratio; 1 M each; pH 1). The second material (EGr-S) was prepared in a salt solution of 0.2 M ammonium sulphate (pH 5). Both materials were morphologically and structurally characterized by SEM, XRD and XPS. The XRD investigation proved that the EGr-A sample contains graphene oxide (GO- 39%) along with few-layer graphene (FLG- 44%) and multi-layer graphene (MLG- 17%). In contrast, the EGr-S sample consists of two-layer graphene (89%) and multi-layer graphene (11%). The performances of two glassy carbon (GC) electrodes modified with the graphene based materials (GC/EGr-A and GC/EGr-S) were investigated towards 8-Hydroxy-2'-deoxyguanosine (8-OHdG) detection and compared with those of bare GC. As expected, the graphene-modified electrodes have a high sensitivity (0.67 A M^-1 cm^-2 for GC/EGr-S and 0.53 A M^-1 cm^-2 for GC/EGr-A), a wide linear range (3 × 10^-7-10^-4 M) and low detection limit (LOD = 9.09 × 10^-8 M). In contrast, the bare electrode has higher detection limit (LOD = 3 × 10^-7 M) and considerably lower sensitivity towards 8-OHdG (0.22 A M^-1 cm^-2).

Keywords: 8-Hydroxy-2′-deoxyguanosine; Electrochemical detection; Graphene; Graphene-modified electrodes.