【摘要】 目的测定磺胺甲噁唑(SMZ)、磺胺嘧啶(SD)和甲氧苄啶(TMP)的离解常数(pKa)。方法毛细管电泳(CE)条件:未涂层的弹性石英毛细管柱(60.2cm×75μm,有效长度50cm),30mol.L-1磷酸盐缓冲液,恒电压,柱温25℃,检测波长214nm;阳极进样,阴极检测。电流突跃标记法测定中性标记物的电泳淌度。分别测定固定缓冲溶液的离子强度或不固定缓冲溶液的离子强度条件下三种化合物的有效淌度,并与pH值进行非线性拟合,测定其离解常数。结果SMZ、SD、TMP的离解常数固定离子强度时,分别为5.69,6.36和6.68;不固定离子强度时分别为5.71,6.35和6.60。结论该方法简便、快速、准确,可用于测定3种磺胺类药物的解离常数,且不受缓冲液离子强度的影响。更多还原

【Abstract】 Objective To develop a simultaneous determination of dissociation constant values(pKa) of sulfamethoxazole(SMZ),sulfadiazine(SD) and trimethoprim(TMP).Methods Capillary electrophoresis(CE) conditions:a fused-silica capillary column(60.2 cm×75 μm,effective length 50 cm) was used,the separation voltage was fixed,the cartridge temperature was 25 ℃,the UV detection wavelength was 214 nm,and sample was introduced from the anode with pressure injection.The mobility of neutral marker was determined with the current sudden change.The effective mobilities of the three compounds on pH were investigated,and their pKa values was determined by nonlinear simulation.Results When the ionic strength of running buffer was fixed,the pKa values of SMZ,SD and TMP were 5.69,6.36 and 6.68,respectively;on the contrary,the pKa values of SMZ,SD and TMP were 5.71,6.35 and 6.60,respectively.Conclusion The proposed method is simple,fast and accurate for determination the pKa values of sulfonamides,and which isn’t affected by the ionic strength of running buffer.更多还原