钯(Ⅱ)-甲氨蝶呤螯合物与亚甲蓝相互作用的共振瑞利散射光谱及其分析应用

Resonance Rayleigh Scattering Spectra of the Interaction of Pd(Ⅱ)-Methotrexate Chelate with Methylene Blue and Their Analytical Application

在pH为4.1～7.0的Britton-Robinson缓冲溶液中,甲氨蝶呤与钯(Ⅱ)相互作用形成1:1的螯合阴离子,并进一步与亚甲蓝(MB)反应形成1:1的离子缔合物.该反应可引起共振瑞利散射(RRS)的显著增强并产生新的RRS光谱,最大RRS波长位于342nm.在一定条件下,散射增强(ΔI)与甲氨蝶呤的浓度成正比,其线性范围为0.008～2.0μg/mL.此方法具有高灵敏度,对于甲氨蝶呤的检出限为2ng/mL.考察了适宜的反应条件和影响因素,研究了共存物质的影响,基于Pd(Ⅱ)-甲氨蝶呤-亚甲蓝体系三元离子缔合物的RRS光谱,发展了一种高灵敏、简便快速测定甲氨蝶呤的新方法.此方法用于人血清和尿样中的甲氨蝶呤的测定获得满意的结果.同时,对三元离子缔合物的结构和反应机理进行了讨论.

In Britton-Robinson buffer of pH 4. 1-7.0, methotrexate reacts with palladium （ Ⅱ ） to form 1 ： 1 anionic chelates. Which react further with methylene blue（MB） to form the ion-association complexes. In this case, the resonance Rayleigh scattering（RRS） intensities are enhanced greatly and new RRS spectra appear. The maximum RRS wavelengths locate at 342 nm. Under given conditions the intensities of RRS are proportional to the concentration of MTX. The linear range is 0. 008-2.0 μg/mL for the system, and the methods have high sensitivities and the detection limits of MTX is 2 ng/mL. The optimum conditions of the reaction, influence factors and the effect of coexisting substances were investigated. A high sensitive, simple and quick method is developed for the determination of MTX. The method can be applied satisfactorily to determination of MTX in serum and urine samples. In addition, the structure of the ternary ion-association complex and their reaction mechanism were discussed.