甲基绿褪色分光光度法测定红霉素

建立了褪色分光光度法测定红霉素肠溶片中红霉素含量的方法。用二次石英蒸馏水为溶剂,甲基绿和红霉素在40℃下可以反应形成稳定的离子缔合物,以试剂空白做参比测定离子缔合物溶液的吸光度,离子缔合物的生成导致吸收光谱发生变化,且在一定范围内吸光度变化值ΔA与红霉素的浓度成正比,红霉素的浓度在0.000 6~0.105 0mg/mL范围内服从Beer定律,在635nm处测得ε=4.23×104 L/(mol·cm)-1,方法检出限达到0.26μg/mL。方法简便快捷,重现性和选择性好,可用于红霉素肠溶片中红霉素含量的测定。

Determination of Erythromycin with Methyl Green Fading Spectrophotometry

We tried to develop a new method for the determination of erythromycin in enteric-coated tablets with spectrophotometry. In the neutral aqueous solution, prepared with secondary quartz distilled water as solvent, methyl green reacts with erythromycin to form ionic complex at 40 ℃. Using blank reagent as a reference, the absorbance of the ionic complex was measured. The formation of ionic complex brings some changes to the absorption spectra. Furthermore, within a certain range of concentration, the absorbance change value△A is proportional to the concentration of erythromycin. When the concentration of erythomycin is in the range of 0. 000 6-0. 105 0 mg/mL, the Beer＇s law is obeyed. The apparent molar absorptivity of the complex ε at 635 nm is 4.23× 104 L/（mol-cm） 1. The detection limit of the method is 0. 26μg/mL. The method is simple with a good reproducibility and selectivity and can be used in the determination of the content of erythromycin in erythromycin enteric-coated tablet.