本文讨论了线性电位滴定法测定弱酸的数学模型，自编了计算程序．样品经溶解后，加入氯 化钡控制离子强度不变，然后分步等量加入氢氧化钠标准溶液，测定其ｐＨ值，输入计算机，按所 编程序求出滴定终点．应用本法测定了盐酸麻黄碱等六种样品，结果与非水滴定法相吻合． This article discusses the linear potentiometric titration of weak acid mathematical model, self-compiled program. After the sample is dissolved, the barium chloride is added to control the ionic strength, and the sodium hydroxide standard solution is added in equal steps in equal steps. The pH value is measured and input into the computer. The end point of the titration is obtained according to the programmed sequence. The determination of six samples of ephedrine hydrochloride by this method is consistent with the non-aqueous titration method.