四环素类抗生素-钨酸钠-乙基紫体系的共振瑞利散射光谱及其分析应用

在pH为9.0的Clark-Lubs缓冲溶液中, 强力霉素、土霉素、四环素和金霉素等四环素类抗生素与钨酸钠反应形成1∶1的阴离子螯合物, 它仅能引起吸收光谱的变化, 不能引起共振瑞利散射(RRS)的增强, 但是当该螯合物进一步与乙基紫反应形成三元离子缔合物时, RRS显著增强并产生新的RRS光谱, 它们具有相似的光谱特征, 最大RRS波长均位于328 nm处. 4种抗生素的线性范围和检出限分别为0.047～4.8 μg•mL^－1和14.1 ng•mL^－1(强力霉素); 0.078～5.0 μg•mL^－1和23.5 ng•mL^－1(土霉素); 0.081～5.7 μg•mL^－1和24.4 ng•mL^－1(四环素); 0.122～7.7 μg•mL^－1和36.6 ng•mL^－1(金霉素). 考察了三元离子缔合配合物的组成, 讨论了配合物的结构和反应机理, 并发展了一种高灵敏、简便快速测定四环素类抗生素的新方法.

Resonance Rayleigh Scattering Spectra of Tetracycline Antibiotics-Sodium Tungstate-Ethyl Violet System and Their Analytical Application

In Clark-lubs buffer of pH 9.0, tetracycline antibiotics (TCs) such as doxycycline (DOTC), oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) react with sodium tungstate to form 1∶1 anion chelates. It results in the change of the absorption spectra of TCs, but the resonance Rayleigh scattering (RRS) intensities are not increased. When the anion chelates further react with ethyl violet, the great enhancements of RRS intensities are observed and new RRS spectra appear. Their spectral characteristics are similar, and the maximum RRS wavelengths are at 328 nm. The linearity range and detection limits of four TCs are 0.047～4.8 μg•mL^－1 and 14.1 ng•mL^－1 (DOTC), 0.078～5.0 μg•mL^－1 and 23.5 ng•mL^－1 (OTC), 0.081～5.7 μg•mL^－1 and 24.4 ng•mL^－1 (TC), 0.122～7.7 μg•mL^－1 and 36.6 ng•mL^－1 (CTC), respectively. The composition of the ternary ion-association complex is investigated, and the structure of the complex and its reaction mechanism are discussed. A high sensitive, simple and fast method is proposed to the determination of TCs.