Graphene oxide quantum dots immobilized on mesoporous silica: preparation, characterization and electroanalytical application

• Published in: RSC advances Vol. 1; no. 52; pp. 3135 - 31315
• Main Authors: Mikhraliieva, Albina, Zaitsev, Vladimir, Tkachenko, Oleg, Nazarkovsky, Michael, Xing, Yutao, Benvenutti, Edilson V
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 24.08.2020; The Royal Society of Chemistry
• Subjects: Antibiotics; Basal plane; Chemistry; Electrode polarization; Electrodes; Endocrine disruptors; Fourier transforms; Functional groups; Graphene; NMR; Nuclear magnetic resonance; Photoelectrons; Porous materials; Quantum dots; Rigid structures; Silicon dioxide; Spectrum analysis; Spinning (materials); Surface area; Trimethoprim
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d0ra04605a

Because of its high surface area and combination of various functional groups, graphene oxide (GO) is currently one of the most actively studied materials for electroanalytical applications. It is not practical to utilize self-supported GO on its own and thus it is commonly integrated with different supporting carriers. Having a large lateral size, GO can only wrap the particles of the support and thus can significantly reduce the surface area of porous materials. To achieve synergy from the high surface area and polyfunctional nature of GO, and the rigid structure of a porous support, the lateral size of GO must essentially be decreased. Recently reported graphene oxide quantum dots (GOQDs) can fulfil this task. Here we report the successful preparation of an SiO 2 -GOQDs hybrid, where GOQDs have been incorporated into the mesoporous network of silica. The SiO 2 -GOQDs emit a strong luminescence with a band maximum at 404 nm. The Raman spectrum of SiO 2 -GOQDs shows two distinct peaks at 1585 cm −1 (G-peak) and 1372 cm −1 (D-peak), indicating the presence of a graphene ordered basal plane with aromatic sp 2 -domains and a disordered oxygen-containing structure. Covalent immobilization of GOQDs onto aminosilica via such randomly structured oxygen fragments was proven with the help of Fourier transform infrared spectroscopy, solid-state cross-polarization magic angle spinning 13 C nuclear magnetic resonance, and X-ray photoelectron spectroscopy. SiO 2 -GOQDs were used as a modifier of a carbon paste electrode for differential pulse voltammetry determination of two antibiotics (sulfamethoxazole and trimethoprim) and two endocrine disruptors (diethylstilbestrol (DES) and estriol (EST)). The modified electrodes demonstrated a significant signal enhancement for EST (370%) and DES (760%), which was explained by a π-π stacking interaction between GOQDs and the aromatic system of the analytes. Graphene oxide quantum dots incorporated into a mesoporous silica network have been used as a modifier of a carbon paste electrode for the determination of antibiotics and hormones.