In this article, a new Spectrofluorometric method was developed for determination of methamphetamine based on turn on luminescence response of captopril-modified Y2O3: Eu3+ nanoparticles (Y2O3:Eu3+ NPs). Y2O3: Eu3+ nanoparticles were characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The fluorescence of captopril-modified Y2O3:Eu3+ at 612 nm was increased in the presence of methamphetamine. Based on this phenomenon, an appropriate method for sensitive assay of methamphetamine was developed. After optimization, fluorescence intensity changes according to the Langmuir binding isotherm equation which is linearly proportional to the concentration of methamphetamine in the range of 0.2–30 M and the detection limit(S/N=3) of 0.144 M. RSD for 4 replicated results of 1 M methamphetamine is 0.18%. All the measurements were carried out 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 methamphetamine.
