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在pH 7.8的磷酸盐缓冲溶液中,琥乙红霉素和甲基绿在50℃下可以反应形成稳定的离子缔合物。冷却至室温后以水做参比测定体系的吸收光谱,发现琥乙红霉素溶液在550~670 nm几乎无吸收,甲基绿在此区域有强烈的吸收,甲基绿与琥乙红霉素生成的离子缔合物的吸光度与甲基绿相比有明显降低,最大褪色波长在634 nm附近,且吸光度变化ΔA与琥乙红霉素的浓度成正比。琥乙红霉素的质量浓度在0.0009~0.1530 mg/mL范围内服从Beer定律,线性回归方程为:A=-3.037ρ+0.0355,r=0.9995;对10.00 mL 5.0×10-3mg/mL琥乙红霉素测定6次,RSD=0.6%,在634 nm测得ε=6.19×104L·mol-1·cm-1。研究了琥乙红霉素-甲基绿反应体系的光谱特性、反应的影响因素、共存物质的影响,做了反应的条件优化实验,对所建立的方法进行了一些初步的分析应用。在实验基础上,建立了测定琥乙红霉素的褪色分光光度法,检出限为0.21μg/mL,可用于琥乙红霉素片中琥乙红霉素含量的测定。
In pH 7.8 phosphate buffer solution, erythromycin ethylsuccinate and methyl green can react at 50 ° C to form a stable ionic association. After cooling to room temperature, the absorption spectrum of the system was determined by reference to water. It was found that erythromycin ethylsuccinate solution had almost no absorption at 550-670 nm. Methyl Green had strong absorption in this region. Methyl Green and erythromyces < Compared with methyl green, the absorbance of the ion-association complex produced by this method was significantly decreased. The maximum fading wavelength was around 634 nm, and the change of absorbance ΔA was proportional to the concentration of erythromycin ethylsuccinate. Beer’s law was obeyed in the range of 0.0009-0.1530 mg / mL with the linear regression equation of A = -3.037ρ + 0.0355, r = 0.9995. For 10.00 mL of 5.0 × 10-3 mg / mL succinimide Erythromycin was measured 6 times with RSD = 0.6% and ε = 6.19 × 104 L · mol-1 · cm-1 measured at 634 nm. The spectral characteristics of erythromycin ethylsuccinate-methyl green reaction system, the influencing factors of the reaction and the influence of coexisting substances were studied. The optimal conditions for the reaction were studied. Some preliminary analytical applications were made to the established methods. On the basis of experiments, the fading spectrophotometric method was established for the determination of erythromycin ethylsuccinate. The detection limit was 0.21μg / mL, which could be used to determine the content of erythromycin ethylsuicate in erythromycin ethylsuccinate.