Ultrasound-aided synthesis of gold-loaded boron-doped graphene quantum dots interface towards simultaneous electrochemical determination of guanine and adenine biomolecules

Graphical abstract
Highlights • Au@B-GQDs nanocomposite was synthesized using the 38 kHz ultrasonicator. • Different shaped AuNPs were anchored onto laterally grown B-GQDs surface. • Au@B-GQDs showed high electrocatalytic activity due to synergistic effect. • Au@B-GQDs showed excellent sensor performance even when interference was present. • Au@B-GQDs resulted in high recovery yield even in real sample analysis.
To acquire substantial electrochemical signals of guanine-GUA and adenine-ADE present in deoxyribonucleic acid-DNA, it is critical to investigate innovative electrode materials and their interfaces. In this study, gold-loaded boron-doped graphene quantum dots (Au@B-GQDs) interface was prepared via ultrasound-aided reduction method for monitoring GUA and ADE electrochemically. Transmission electron microscopy-TEM, Ultraviolet–Visible spectroscopy-UV–Vis, Raman spectroscopy, X-ray photoelectron spectroscopy-XPS, cyclic voltammetry-CV, and differential pulse voltammetry-DPV were used to examine the microstructure of the fabricated interface and demonstrate its electrochemical characteristics. The sensor was constructed by depositing the as-prepared Au@B-GQDs as a thin layer on a glassy carbon-GC electrode by the drop-casting method and carried out the electrochemical studies. The resulting sensor exhibited a good response with a wide linear range (GUA = 0.5–20 μM, ADE = 0.1–20 μM), a low detection limit-LOD (GUA = 1.71 μM, ADE = 1.84 μM), excellent sensitivity (GUA = 0.0820 µAµM−1, ADE = 0.1561 µAµM−1) and selectivity with common interferents results from biological matrixes. Furthermore, it seems to have prominent selectivity, reproducibility, repeatability, and long-lasting stability. The results demonstrate that the fabricated Au@B-GQDs/GC electrode is a simple and effective sensing platform for detecting GUA and ADE in neutral media at low potential as it exhibited prominent synergistic impact and outstanding electrocatalytic activity corresponding to individual AuNPs and B-GQDs modified electrodes.