Development of a coordination polymer/agarose hydrogel-based nanoprobe for thiopental determination in exhaled breath condensate.

This study aimed to develop a fluorescent probe for thiopental quantification in exhaled breath condensate (EBC) samples. The probe was designed based on the favorable coordination and photoluminescent properties of Tb³⁺ and pyridine-2,6-dicarboxylic acid (PDCA) embedded into the agarose hydrogel substrate, enabled a simple, rapid, and non-invasive approach suitable for biological samples. This platform exhibited a linear response in a concentration range of 0.05 to 3.0 µg mL- 1 and achieved a detection limit of 0.001 µg mL- 1. When the hydrogel nanocomposite-based probe was used for five replicated measurements of thiopental, it produced relative standard deviations of 2.1% for intra-day and 3.9% for inter-day analyses. Its applicability to EBC samples suggested potential value for anesthetic monitoring and clinical toxicology. As the first report employing a Tb-PDCA/agarose hydrogel for thiopental analysis, this work provided a foundation for further investigations aimed at improving sensitivity, evaluating selectivity in complex clinical matrices, and validating performance in larger patient populations.