交流示波极谱滴定可有效地应用于四苯硼钠滴定甲基硫酸新斯的明。先加入四苯硼钠,使之与新斯的明产生沉淀,然后以硫酸亚铊标准溶液滴定多余的四苯硼钠。以dE/dt—E曲线上四苯硼钠切口的消失为终点。用此法测定了注射液中新斯的明含量,回收率为99.3～100.2％,十次测定的相对标准偏差为0.42％。远较药典方法方便、快速。 AC Oscillopolarographic titration can be effectively applied to sodium tetraphenylborate titration of neostigmine methylsulfate. Sodium tetraphenylborate is first added to cause precipitation with neostigmine, and titration of the excess sodium tetraphenylborate with a thallium sulfate standard solution. The dE / dt-E curve on the disappearance of sodium tetraphenylborate as the end point. The neostigmine content of the injection was determined by this method. The recovery was 99.3% ~ 100.2%. The relative standard deviation of ten determinations was 0.42%. Pharmacopoeia method is far more convenient and faster.