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在pH4.0～5.0的弱酸性介质中,Ce(Ⅳ)能与诺氟沙星(NOR)、环丙沙星(CIP)、培氟沙星(PE)、洛美沙星(LOM)和司帕沙星(SPA)等氟喹诺酮类抗生素(FLQs)反应,并最终形成Ce(HL)(OH)4型的三元混配络合物.此时,仅能引起吸收光谱的微小变化和摩尔吸光系数(ε)的少量提高,但是却能导致共振瑞利散射(RRS)的显著增强,5种体系的最大散射波长均位于381nm附近,并在534nm处出现一个较小的散射峰,散射增强(ΔI)在一定范围内与FLQs的浓度成正比,方法有高灵敏度,对不同的FLQ其检出限(3σ)除SPA(16.0μgmL-1)之外,其余FLQs在1.9～5.3ngmL-1之间.研究了Ce(Ⅳ)与FLQs相互作用对RRS光谱的影响,反应的适宜条件和影响因素,考察了共存物质的影响,表明方法有良好的选择性,可用于某些样品中FLQs的测定.还结合吸收光谱的变化和量子化学计算,讨论了反应机理及散射增强的原因.
Ce (IV) can react with norfloxacin (NOR), ciprofloxacin (CIP), pefloxacin (PE), lomefloxacin (LOM) (FLQs) such as streptozotocin (SPA), and eventually form ternary mixed complexes of Ce (HL) (OH) 4 type.At this time, only slight changes in the absorption spectrum and molar A small increase in the extinction coefficient (ε) led to a significant increase in Resonance Rayleigh scattering (RRS). The maximum scattering wavelengths of the five systems were all around 381 nm with a small scattering peak at 534 nm and enhanced scattering (ΔI) is proportional to the concentration of FLQs within a certain range. The method has high sensitivity. The detection limits (3σ) for different FLQs except for SPA (16.0 μg mL-1), and the remaining FLQs ranged from 1.9 to 5.3 ng mL -1 The effects of the interaction between Ce (Ⅳ) and FLQs on the RRS spectrum, the suitable reaction conditions and influencing factors were studied, and the influence of the coexisting substances was investigated. The results showed that the method has good selectivity and could be used for FLQs in some samples In addition, the reaction mechanism and the reason of scattering enhancement are also discussed in combination with the change of absorption spectrum and quantum chemistry calculation.