多元校正电位滴定法同时测定苯甲酸和水杨酸

建立了一种可同时测定苯甲酸和水杨酸的电位滴定新方法.在这种方法中,滴定剂是氢氧化钠与氯化钾的混合溶液,被滴定液中同时插入了pH指示电极和氯离子指示电极.在滴定过程中的任一滴定点,溶液的pH和滴定剂的加入体积可由两个电极的电位测定值同时获得,从而可应用多元校正法由相应的滴定曲线求得混合酸中每一种酸的含量.该方法免去了滴定剂体积的直接读取,且不需确定滴定终点,因此该法简便、精确.应用本方法对样品中的苯甲酸和水杨酸进行了同时测定,结果满意.

Simultaneous Determination of Benzoic Acid and Salicylic Acid by Potentiometric Titration Coupled with Multivariate Calibration Method

A new potentiometric titration method coupled with multivariate calibration method for the simultaneous determination of benzoic acid and salicylic acid has been developed.In this method,the titrant is a mixture of sodium hydroxide and potassium chloride,both pH indicated electrode and chloride ion indicated electrode are inserted in the titration solution.In a process of titration,both the added volume of titrant and the solution acidity at each titration point can be obtained simultaneously from two electrodes,and then the concentration of each component in the mixture can be obtained from the titration curves by multivariate calibration method.The method is free of volumetric measurements,and is independent of titration end point.So the method is simple,convenient and precise.The method has been applied to the simultaneous determination of benzoic acid and salicylic acid in mixture samples with satisfactory results.