Development of a terbium-based coordination polymer nanoprobe for determination of clonazepam in exhaled breath condensate.

Introduction: Clonazepam is a long-acting benzodiazepine utilized for conditions such as seizures, panic disorder, and other neurological/psychiatric disorders. It functions by increasing GABA effects, which leads to reduced neural activity. Careful dosage titration and monitoring are necessary due to potential side effects, including drowsiness, impaired motor coordination, memory loss, and dependence. Methods: In this work, an optical probe based on a terbium (Tb) coordination polymer was developed for the quantification of clonazepam in the exhaled breath condensate (EBC). The principle of the probe was based on the interaction of clonazepam with pyridine-2,6-dicarboxylic acid -Tb coordination polymer nanoparticles, which dynamically quenches the Tb³⁺ luminescence through a collisional mechanism, as confirmed by the linear Stern-Volmer plot and the increased quenching efficiency at higher temperatures. As the increase in response intensity is proportional to clonazepam concentration, a method was offered for its determination in EBC samples. Results: This method presented a linear relationship with clonazepam concentration in the range of 0.001-1.5 µg.mL Conclusion: By being faster, simpler, and cost-effective than traditional techniques, this method presented a valuable tool for therapeutic drug monitoring.