Raman Spectroscopy as an Analytical Tool for Characterization of Fluoroquinolones

Abstract

The aim of this paper is to produce the basis for the Raman spectroscopy as a promising new official method for identification of fluoroquinolone antibacterials. Raman spectroscopic analysis data for three pure fluoroquinolone antibacterials like Norfloxacin, Ciprofloxacin and Ofloxacin, have been performed by a low resolution portable Raman Spectrometer (Raman system R-3000) using 785 nm solid state diode laser and having fibre optic sampling probe. The Raman spectra are collected over the wave number range from 140 to 2500 cm-1 at room temperature. From our overall Raman spectroscopic analysis, it has been found that those fluoroquinolones show prominent characteristic peaks for pyridone nucleus, piperazinyl ring, carboxylic acid and fluorine substituent. In addition, the characteristic peaks at 872.7, 771.47 and 797.5 cm -1 for Norfloxacin, Ciprofloxacin and Ofloxacin, respectively, are assigned to fully symmetric vibrational normal mode of the molecule containing the C-F bond. Since the important characteristic groups are available in all the cases, their Raman spectral pattern is more or less similar. From the above-mentioned information, it can be concluded that Raman spectroscopic analysis, a non-destructive method with minimal water interference, may also be used as a useful tool for the identification of compounds, specially the fluoroquinolones.