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

Abstract

Detection of sialic acid using advanced sensors in milk-based products is essential in the food industry. Therefore, the present work reports 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 toward the detection of sialic acid. Here, boronic acid surface decoration on S/N-dGQD was confirmed by several spectral characterizations. The addition of different quantities of sialic acid results in a directly proportionate correlation to fluorescence quenching. It gives a broad linear range of 50 ng/mL to 1000 ng/mL and a limit of detection of 6.04 ng/mL. Also, it displayed remarkable selectivity, likely due to interaction of sialic acid-containing 1,2-diol with hydroxyl group of Boro-S/N-dGQDs nanoprobe. Designed sensor demonstrated good stability and reproducibility. Real-time analysis of sialic acid in different milk-based products confirmed practicability of Boro-S/N-dGQDs.