A rapid and sensitive resonance Rayleigh scattering spectra method for the determination of quinolones in human urine and pharmaceutical preparation

Abstract

A new method based on resonance Rayleigh scattering (RRS) was proposed for the determination of quinolones (QNS) at the nanogram level. In pH 3.3-4.4 Britton-Robinson buffer medium, quinolones such as ciprofloxacin, pipemidic acid (PIP), lomefloxacin (LOM), norfloxacin (NOR) and sarafloxacin (SAR) were protonated and reacted with methyl orange (MO) to form an ion-pair complex, which then further formed a six-membered ring chelate with Pd(II). As a result, new RRS spectra appeared and the RRS intensities were enhanced greatly. RRS spectral characteristics of the MO-QNS-Pd(II) systems, the optimum conditions for the reaction, and the influencing factors were investigated. Under optimum conditions, the scattering intensity (∆I) increments were directly proportional to the concentration of QNS with in certain ranges. The method had high sensitivity, and the detection limits (3σ) ranged from 6.8 to 12.6 ng/mL. The proposed method had been successfully applied for the determination of QNS in pharmaceutical formulations and human urine samples. In addition, the mechanism of the reaction system was discussed based on IR, absorption and fluorescence spectral studies. The reasons for the enhancement of scattering spectra were discussed in terms of fluorescence-scattering resonance energy transfer, hydrophobicity and molecular size.

Resonance Rayleigh Scattering as a Tool for Isoelectric Point Monitoring and Iron(III) Cation Determination

“…Therefore, the RRS spectra can be utilized to speculate molecular structure, charge distribution, and state of combination. Recently, the RRS technique has been widely applied to sensing metal ions, 8,9 biological molecules, [10][11][12] hazardous pollutants, 13,14 drug molecules, [15][16][17] dyes, [18][19][20] and so on. [21][22][23] The iron(III) cation is one of trace metal elements that play an important role in environmental and biological systems.…”

Applying resonance Rayleigh scattering and spectrofluorimetric techniques for the selective determination of neomycin sulfate using Congo red as a probe: Applications for wastewater analysis

“…To date, the RRS method has been widely used for the determination of trace substances, for example, nucleic acids, [28] proteins, [29] inorganic ions, [30,31] organic compounds, [32,33] drugs, [34][35][36] etc. [37][38][39] Recent studies have shown that the RRS method can be also applied to the determination of antibiotics such as fluoroquinolones, [40,41] cephalosporins, [42] tetracyclines, [43] macrolides, [44] aminoglycosides, [45] etc. In the past few years, there have been reports on the quantitative analysis of NEO using the RRS method.…”