Mesoporous silica encapsulated wheat straw derived carbon dots functionalized with Schiff base silane pockets: a...

A mesoporous silica-encapsulated wheat straw-derived carbon dots functionalized with Schiff base silane pockets (m-SiO₂_ws-CDs@SBs) has been developed. m-SiO₂_ws-CDs@SBs provides a synergistic platform that integrates the benefits of each component, including the optical properties of CDs, the high surface area and robustness of m-SiO₂, and the molecular recognition capabilities of Schiff bases. The fluorescence of m-SiO₂_ws-CDs@SBs remained constant, whereas upon the addition of aspirin (ASP), the fluorescence of m-SiO₂_ws-CDs@SBs was quenched. m-SiO₂_ws-CDs@SBs exhibit high sensitivity (limit of detection = 3.69 nM), linearity over a concentration range between 18-140 nM with R ² of 0.9809. The m-SiO₂_ws-CDs@SBs showed pronounced fluorescence quenching towards ASP and excellent selectivity for ASP in the presence of other pharmaceutical drugs, i.e., diclofenac, ibuprofen, naproxen, and mefenamic acid. Moreover, it displayed negligible interference from common excipients and metal ions at 1 : 1 and 1 : 10 molar ratios of ASP and interferent, respectively. The fluorescent probe has been used to analyze ASP in an aspirin drug product available at a local pharmacy, as well as in tap water and river water with an excellent recovery of 95.00-99.44%.