Abstract:

In 5.0 mol/L HCl buffer solution, phosphowolframic acid(Pwa) could react with moxifloxacin(MXFX) and gatifloxacin(GTF) fluoroquinolone antibiotics(FLQs) to form 1∶1 ion-associated complexes respectively. The reactions resulted in great enhancement of resonance Rayleigh scattering(RRS) and new RRS bands appear. The reaction products of the two drugs had similar spectral characteristics, and the maximum RRS wavelength was located at 320 nm. The intensities of RRS are proportional to the concentration of antibiotics, the linearity ranges of two fluoroquinolone antibiotics are 0.025~6.0 mg/L(MXFX) and 0.023~9.0 mg/L(GTF), respectively. Therefore, a new method for determination of the drugs could be developed and applied to the determination of FLQs in capsules and human urine samples. The reaction mechanism and the reasons for RRS enhancement of the system were investigated.

Key words: Moxifloxacin, Gatifloxacin, Phosphowolframic Acid, Resonance Rayleigh Scattering Spectra