Application of a lanthanide composite nanoparticle‐sensitized luminescence method for the determination of salicylic acid in pharmaceutical formulations and human plasma

Terbium‐acetylacetone (Tb–acac) composite nanoparticles were 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 fluorimetric probes in the determination of salicylic acid (SA), based on the fluorescence enhancement of nanoparticles through fluorescence resonance energy transfer (FRET). The influence of buffer solution was investigated. Under the optimum conditions, a linear calibration graph was obtained over the SA concentration range 5 × 10^–7–1 × 10^–4 mol/L. The limit of detection was found to be 2.5 × 10^–8 mol/L. The relative standard deviation (RSD) for six repeated measurements of 1 × 10^–4 mol/LSA was 1.75%. The method was applied to the determination of SA in pharmaceutical formulations and human plasma. We believe that the proposed approach has great potential for clinical purposes. Copyright © 2008 John Wiley & Sons, Ltd.