[Study on the enhancement diphacinone-europium fluorescence system and application for determination of the residue in urine].

ABSTRACT

OBJECTIVE: To establish an accurate, convenient and sensitive quantitative fluorescence method for the determination of diphacinone (DPN) in urine. METHODS: Diphacinone was complexed with europium ion (Eu3+) at the presence of DL-histidine, polyvinylpyrrolidone (PVP) and ammonia-ammonium chloride (NH3 -NH4 Cl) buffer solution to form a multiple complex of DPN-Eu(3+) -DL-histidine-NH3-PVP fluorescence system, and the fluorescence sensitivity was greatly enhanced by the rare earth element of yttrium ion (Y3+ ). The excitation and emission wavelengths were 330 nm and 612 nm, respectively. RESULTS: The optimum conditions were Eu3+ 10.0 mg/L,Y3+ 20.0 mg/L, DL-histidine 0.01%, PVP 0.05% at pH 9.0. Under the optimum conditions, fluorescence intensity of the system was a linear function of the concentration of diphacinone in the range of 0.2 - 10.0 mg/L, the limit of quantification was 0.2 mg/L. The spiked recoveries for DPN in urine were 87.0% - 97.3%, the intra-and inter-day RSDs were between 3.4% - 4.7% and 4.8% - 6.6%, respectively. CONCLUSION: The established method is simple, accurate and reliable, and it is satisfactory for the determination of DPN in urine and can be used for DPN poisoned patients for the rapid clinical diagnosis.