Spectrofluorimetric determination of sparfloxacin using europium(III) as a fluorescence probe in micellar medium

A europium (III)-sensitized, spectrofluorimetric (FL) method is presented for the determination of sparfloxacin (SPAR) using an anionic surfactant, sodium dodecyl benzene sulphonate (SDBS). The method is based on the strong fluorescence (FL) enhancement of SPAR after the addition of Eu³⁺ ions as fluorescence probes. The experimental results indicated that the FL intensity of the SPAR-Eu³⁺ system was enhanced markedly by SDBS. The maximum FL emission signal was obtained at about 615 nm when excited at 372 nm. The experimental conditions that affected the FL intensity of the SPAR-Eu ³⁺-SDBS system were optimized systematically. The enhanced FL intensity of the system exhibited a good linear relationship with the SPAR concentration over the range of 1.5 × 10^-9 - 1.2 × 10^-7 mol L^-1 with a correlation coefficient (r) of 0.9987. The limit of detection (3δ) was 4.15 × 10^-10 mol L ^-1with a relative standard deviation (RSD) of 1.65%. This method was successfully applied for the determination of SPAR in pharmaceuticals, and human serum and urine samples with higher sensitivity, wide dynamic range and better stability. The possible interaction mechanism of the system is also discussed in detail by ultraviolet absorption spectra and FL spectra.