Europium Fluorescent Probe And Applications In The Analysis Of Medicament And Dna

The fluorescence of lanthanide chelates features a wide Stokes shift (>150 nm), narrow emission band (<10 nm) and long lifetime which has attracted much attention.A time-resolved fluorescence analysis method was developed using europium (Ⅲ) ion as fluorescent probe for the determination of pipemidic acid (PPA). Intramolecular energy transfer occurs in the europium complex with PPA and the characteristic fluorescence of europium (Ⅲ) ion emiting at 616 nm is excited by UV light at 274 nm. Effects of experimental conditions on the fluorescence intensity were discussed. Experimental results showed that in the Tris-HC1 buffer solution with pH 8.2, when the appropriate amounts of surfactant SDS were added, the fluorescence intensity of the system was greatly increased. At the optimum conditions, a detection limit of 2x10-8 mol/L PPA was obtained with a RSD of 0.6%(2.00×10-6 mol/L, n=11). The linear relationship of△I=0.9014 C (×10-8 mol/L)+11.23 (r=0.9998) between fluorescence signals and the concentrations of pipemidic acid was obtained in the range of 5.00×10-8-5.00×10-6 mol/L. The method has been applied to the determination of PPA in tablet and urine samples. The results are satisfied, shown by the good agreement with that obtained via standard method in codex and good recoveries of standard PPA spiked in diluted urine samples.It is well-known that the fluorescence intensity of DNA itself is weak, so that the direct application of its fluorescence emission properties has been limited. PPA could form the coordination complex with Eu3+, which emits the characteristic fluorescence of Eu3+, and the fluorescence intensity of the system is greatly increased when DNA is added. Herein, the fluorescence intensity of PPA-Eu3+ complex enhanced by herring sperm DNA was studied, and a simple and sensitive fluorescence method for the determination of herring sperm DNA by time-resolved fluorescence was developed. The detection limit of herring sperm DNA was 0.03 mg/L with the RSD of 0.3%(4.0 mg/L, n=11) and the linear range was 0.1-6.0 mg/L. This method has been applied to the determination of herring sperm DNA in synthetic samples successfully.