Detection of β-Hydroxybutyric Acid Based on a Fluorescent Probe of Lanthanide Complexes

In this paper, a lanthanide complex-based fluorescent sensor Tb(4-MBA) was developed for the selective recognition of diabetic ketoacidosis (DKA) and the diabetes biomarker β-hydroxybutyric (β-Hb). β-Hb significantly enhanced the fluorescence emission of the Tb(4-MBA) complex at 539  nm. Based on the analysis of the surface electrostatic potential distribution and time-resolved spectra, we speculate that in the reaction system of β-Hb with Tb(4-MBA), β-Hb and Tb(4-MBA) may form a complex through hydrogen bonding interactions, which brings β-Hb closer to Tb³⁺ and thus reduces the non-radiative energy loss of the solvent molecules to Tb³⁺ and significantly enhances the Tb(4-MBA) fluorescence intensity. The linear range of Tb(4-MBA) for β-Hb was 2-55 μM, and the limit of detection (LOD) was 50.6 nM. This sensor has high sensitivity and selectivity and shows great potential in the field of screening and diagnosis of diabetes mellitus and DKA.