Synthesis of Bone Meal-derived 4-Carboxyphenylboronic Acid Functionalized Sulfur and Nitrogen Co-doped Graphene Quantum Dots Nanoprobe for Sialic Acid Sensing

Detecting sialic acid using sensor-based technology in milk-based products is crucial. Therefore, present work reported the sulfur and nitrogen-doped graphene quantum dots from bone meal functionalized with boronic acid (Boro-S/N-dGQDs) nanoprobe for sialic acid sensing applications. Briefly, S/N-dGQDs were functionalized with 4-carboxyphenylboronic acid to improve performance of fluorescent sensors for detection of sialic acid. The boronic acid surface decorating on S/N-dGQD was confirmed by several spectral characterizations. Addition of varying quantities of sialic acid results in a directly proportionate correlation to fluorescence quenching. As a result, it has a broad linear range of 50 ng/mL to 1000 ng/mL and a limit of detection of 6.04 ng/mL. It also displayed remarkable selectivity, likely due to interaction of sialic acid-containing 1,2-diol with hydroxyl group of Boro-S/N-dGQDs nanoprobe. Boro-S/N-dGQDs demonstrated good stability, reproducibility and real-time analysis of different milk-based products for presence of sialic acid confirmed practicability of fluorescent Boro-S/N-dGQDs sensor.