胶束电动毛细管色谱法分析头孢哌酮与其S-异构体等杂质

Separation of Cefoperazone and Its S-Isomer and Other Related Substances by Micellar Electrokinetic Capillary Chromatography

以十二烷基硫酸钠(SDS)胶束为准固定相,考察了头孢哌酮、头孢哌酮S-异构体、头孢哌酮杂质A及其他未知杂质在胶束电动毛细管色谱(MECC)分离模式下的分离行为。研究了运行缓冲液的pH值、磷酸盐浓度、SDS浓度、甲醇体积分数、分离电压、分离温度等因素对头孢哌酮、S-异构体、头孢哌酮杂质A及其他杂质的迁移时间、分离度以及可分离出的杂质个数的影响。结果发现,这些因素对头孢哌酮与诸杂质间的分离及检测有显著的影响,尤以pH值为最。它不仅影响它们的迁移时间和分离效率,还直接影响头孢哌酮及其杂质峰的检测。优化后的分离条件:运行缓冲液为70mmol/L磷酸盐-100mmol/LSDS(pH6.5),分离电压为15kV,分离温度为25℃。在此条件下,用非涂渍石英毛细管51.0cm×75μm(有效长度42.5cm),压力进样5kPa×5s,在254nm波长下进行检测,可分离出28个杂质,诸杂质彼此间及与头孢哌酮间可得到有效分离。并将该方法成功地用于测定注射用头孢哌酮钠的含量和有关物质,结果令人满意。

The separation of cefoperazone, its S-isomer, impurity A and other unknown related substances by micellar electrokinetic capillary chromatography （MECC） using sodium dodecyl sulphate （SDS） as the micellar phase was investigated. The effects of pH, concentration of phosphate buffer solution, SDS micelle concentration, methanol volume fraction, applied voltage and temperature on the separation were studied. It was found that the migration of these compounds was affected by these factors, especially by pH of the solution. The elution, as well as the migration time and separation efficiency of cefoperazone, its S-isomer, impurity A and other related substances changed with the acidity of the solution. The optimized separation conditions consisted of a running buffer of 70 mmol/L sodium phosphate buffer, at pH 6.5, containing 100 mmol/L SDS, with an applied voltage of 15 kV and a temperature of 25 ℃. An uncoated fused-silica capillary ofS1.0 cm ×75 μm （42.5 cm of effective length） was used. The sample was injected into the column by pressure （5 kPa） for 5 s. The detection wavelength was set at 254 nm. Twenty-eight impurities in cefoperazone sodium could be detected. Cefoperazone sodium and the degradation products could be separated well. The method was applied to separate and determine cefoperazone and its related substances successfully.