National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca, Romania.
Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany Janos 11, Cluj-Napoca, Romania.
Talanta. 2019 May 1;196:182-190. doi: 10.1016/j.talanta.2018.12.051. Epub 2018 Dec 18.
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 HSO and HNO (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 cm for GC/EGr-S and 0.53 A M cm for GC/EGr-A), a wide linear range (3 × 10-10 M) and low detection limit (LOD = 9.09 × 10 M). In contrast, the bare electrode has higher detection limit (LOD = 3 × 10 M) and considerably lower sensitivity towards 8-OHdG (0.22 A M cm).
本文首次提出了一种通过电流脉冲（脉冲持续时间为 2.5s，两个脉冲之间的停顿时间为 0.8s）剥离石墨棒来合成基于石墨烯的材料的新方法。与传统方法（直流电流剥离）相比，该方法具有几个优点，例如防止电解液过热、在最终样品中产生较少的石墨材料、提高合成产率以及在保持合成参数的情况下提高样品质量的可重复性。第一种材料（EGr-A）是在由 HSO 和 HNO（3:1 比例；1 M 各；pH 1）组成的强酸性溶液中获得的。第二种材料（EGr-S）是在 0.2 M 硫酸铵盐溶液（pH 5）中制备的。两种材料均通过 SEM、XRD 和 XPS 进行了形态和结构表征。XRD 研究证明，EGr-A 样品含有氧化石墨烯（GO-39%）以及少层石墨烯（FLG-44%）和多层石墨烯（MLG-17%）。相比之下，EGr-S 样品由两层石墨烯（89%）和多层石墨烯（11%）组成。对两种玻璃碳（GC）电极进行了基于石墨烯材料（GC/EGr-A 和 GC/EGr-S）的修饰，并对其进行了 8-羟基-2'-脱氧鸟苷（8-OHdG）检测性能的研究，并与裸 GC 电极的检测性能进行了比较。正如预期的那样，石墨烯修饰电极具有高灵敏度（GC/EGr-S 为 0.67 A M cm，GC/EGr-A 为 0.53 A M cm）、宽线性范围（3×10-10 M）和低检测限（LOD=9.09×10 M）。相比之下，裸电极具有更高的检测限（LOD=3×10 M）和对 8-OHdG 的灵敏度（GC/EGr-S 为 0.22 A M cm）要低得多。
