两维pH滴定法同时测定混合极弱酸碱

Simultaneous Determination of Mixture of Very Weak Acids or Bases by Two-dimensional pH-Titration

两维ｐＨ滴定法同时测定混合极弱酸碱朱仲良，李通化，鲁准军（同济大学化学系，上海，２０００９２）关键词两维ｐＨ滴定，极弱酸碱，同时测定，主成分回归法传统的酸碱滴定法必须根据滴定过程中的ｐＨ突跃确定等当点，因此当弱酸（或弱碱）的浓度和离解常数之积ＣＫ＜１...

A new method,two-dimensional pH-titration, for simultaneous determination of mixture of very weak acids or bases is proposed.Titration volume data matrix is measured at different fixed pH values.Principal component regression is carried out to simultaneously determine every component in the mixtures.The systematic deviations of pH measurement do not affect the accuracy of determination results.The mixtures of p-chlorophenol and o-chlorophenol and the mixtures of citrate and tartrate are determined.The relative error is lower than 0.5% and 1%, respectively. Effects of the resolution △pKa and sampling interval △ pH are studied.The relative error is lower than 1%when △pKa △ >0. 4 and △pH=0.1.