Resonance Rayleigh Scattering Spectra, Nonlinear Scattering Spectra of Selected Cephalosporins-Cd(II) Chelate with Titan Yellow and Their Analytical Applications

Three simple and highly sensitive methods were designed for the determination of cephalosporins antibiotics (CFs) such as cefpodoxime proxetil (CFPD), cefdinir (CFDN), and cefuroxime axetil (CFRX) by means of the enhancement effect on resonance Rayleigh scattering (RRS) and non-linear scattering such as second-order scattering (SOS) and frequency doubling scattering (FDS) intensities. All CFs under this project reacts with Cd(II) in BR buffer medium of pH 3.4 to form 1:1 cationic chelate which further react with titan yellow to form 2:1 ion association complexes as a result, RRS, SOS, and FDS intensities were markedly enhanced. The increments of scattering intensities were directly proportional to the concentration of CFs antibiotics in a certain range. The detection limit for the three CFs were 1.73-2.38 ng ml(-1) for RRS method, 5.12-5.67 ng ml(-1) for SOS, 6.25-7.26 ng ml(-1) for FDS method, respectively. Among them the RRS method exhibited the highest sensitivity and the CFPD system was more sensitive then other antibiotics systems. The optimum reaction conditions, the effects of coexisting substances, the structure of ternary complexes, and the reaction mechanism were discussed. The methods were applied to the determination of CFs in pharmaceutical samples with satisfactory results.