Spectrofluorimetric study of the interaction between europium(III) and moxifloxacin in micellar solution and its analytical application

A sensitive spectrofluorimetric method has been developed for the determination of moxifloxacin (MOX) using europium(III)–MOX complex as a fluorescence probe in the presence of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS). The fluorescence (FL) intensity of Eu3+ was enhanced by complexation with MOX at 614 nm after excitation at 373 nm. The FL intensity of the Eu3+–MOX complex was significantly intensified in the presence of SDBS. Under the optimum conditions, it was found that the enhanced FL intensity of the system showed a good linear relationship with the concentration of MOX over the range of 1.8 × 10−11–7.3 × 10−9 g mL−1 with a correlation coefficient of 0.9998. The limit of detection of MOX was found to be 2.8 × 10−12 g mL−1 with relative standard deviation (RSD) of 1.25% for 5 replicate determination of 1.5 × 10−8 g mL−1 MOX. The proposed method is simple, offers higher sensitivity with wide linear range and can be successfully applied to determine MOX in pharmaceutical and biological samples with good reproducibility. The luminescence mechanism is also discussed in detail with ultraviolet absorption spectra.

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► We represent a sensitive fluorimetric method to determine moxifloxacin using Eu3+.
► Characteristic fluorescence of Eu3+–MOX complex is enhanced in micellar solution.
► MOX concentrated at picogram level in a sample is determined by this method.
► The method is applicable to determine MOX in pharmaceutical and biological samples.