Determination of enoxacin using Tb composite nanoparticles sensitized luminescence method.

In our study, terbium-acetylacetone (Tb-acac) composite nanoparticles have been prepared under vigorous ultrasonic irradiation. The nanoparticles are water soluble, stable and have extremely narrow emission bands and high internal quantum efficiencies. They were used as fluorescence probes in the determination of enoxacin (Enox) based on the fluorescence enhancement of nanoparticles through fluorescence resonance energy transfer (FRET). The influence of buffer solution on the fluorescence intensity was investigated. Under the optimum conditions, the fluorescence intensity of the Tb-acac-Enox system is linearly proportional to the Enox concentration in the Enox concentration range of 2 x 10(-7)-1 x 10(-4) M. The correlation coefficient for the calibration curve was 0.9976. The limit of detection as defined by IUPAC, C (LOD) = 3S (b)/m (where S (b) is the standard deviation of the blank signals and m is the slope of the calibration graph) was found to be 3 x 10(-8) M. The relative standard deviation (RSD) for six repeated measurements of 1 x 10(-4) M Enox was 1.35%. The method was applied to the determination of Enox in pharmaceutical formulation and recovery results were obtained from urine samples.