Preparation of a novel fluorescence probe of terbium composite nanoparticles and its application in the determination of ascorbic acid

NovelTb/acetylacetone (acac)/poly (acrylic acid) (PAA) composite nanoparticles were successfully synthesized using the ultrasonic method. 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 ascorbic acid (Vc) based on the fluorescence quenching of nanoparticles in the presence of ascorbic acid. The method is based on the complexation between ascorbic acid and nanoparticles in the absence of the oxidant. The influence of different buffers and concentration of the nanoparticles on the relative fluorescence intensity was tested, and Tris-HCl buffer solution proved to be the best. Under the optimum conditions, a liner calibration graph was obtained over the Vc concentration range of 0.05 - 10 mu g mL(-1). The corresponding detection limit is 0.008 mu g mL(-1) and the relative standard deviation is 1.4% for 0.5 mu g mL(-1) (n = 7). The method proved to be simple, rapid, and specific, and the recovery and relative standard deviation are very satisfactory. A mechanism explaining the process is also presented.