Purpose To investigate the partition of several kinds of cephalosporins in two-phase system composed of hydrophilic organic solvent, inorganic salt and water, such as acetonitrile/NaCl system. Methods The phase diagram of acetonitrile/NaCl system was made by titration. Cephalosporin concentration was determined by HPLC. Results Cephalosporin concentration and temperature affected the partition of cephalosporins a little. NaCl concentration and acetonitrile concentration affected the partition at certain degree. When these concentrations increased, cephalosporins were moved from top phase ( acetonitrile phase) to bottom phase ( salt phase). The effect of pH on the partition was great. At low pH, cephalosporins were distributed mainly at top phase. When pH increased to 3.8, most of cephalosporins were transferred to bottom phase. Conclusion It is practicable to extract cephalosporins by adjusting pH of the two-phase system.%目的 研究几种头孢菌素类抗生素在亲水有机溶剂、无机盐和水组成的双相体系(乙腈/NaCl体系)中的分配规律.方法 用滴定法制作体系的相图,HPLC测定头孢菌素在两相中的浓度.结果 头孢菌素浓度和温度对头孢菌素的分配影响不大;NaCl浓度和乙腈浓度则有一定影响,两者浓度的增加都使头孢菌素向下相(盐相)转移;pH对头孢菌素的分配有较大影响,pH很低时头孢菌素主要分配在上相(乙腈相),pH升高到3.8左右大部分头孢菌素即转移到下相.结论 通过调节pH,用亲水有机溶剂/盐双相体系萃取分离头孢菌素类抗生素是可行的.
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