Luminescenc,e spectrophotometry is widely used in various areas relevant to physical, chemical biological and medical sciences [1]. Due to the high surface to volume ratio of NPs, this feature significantly enhanced the luminescence intensity of them. Lanthanides nanoparticles display characteristic luminescence properties of the central lanthanide ion due to energy transfer processes. Rare earth ions show strong, narrow, long lifetime emissions in all the wavelength ranges because of their inner 4f-4f transition characteristics [2]. The features of lanthanide-based nanoparticles such as large Stoke shift, sharp luminescence, high chemical stability, and thermal durability and nontoxicity nature make them suitable for biosensors. In this article, a new spectrophotometric method for the determination of methamphetamine based on the luminescence response of captopril-modified Y2O3 nanoparticles (Y2O3 NPs) was developed. The fluorescence of Y2O3 NPs sat 612 nm was increased in the presence of methamphetamine. Based on this, an appropriate method for sensitive assay of methamphetamine was described. After optimization, the change of fluorescence intensity is linearly proportional to the concentration of methamphetamine in the range of 0.2–30 M, and the detection limit is 1.44 M. All the measurements were completed in biological pH at the room temperature under ambient conditions. The sensing mechanism was suggested to arise from fluorescence enhancement induced by the interaction between modified NPs and analyte.
