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645981 
Journal Article 
Process monitored spectrophotometric titration coupled with chemometrics for simultaneous determination of mixtures of weak acids 
Liao, L; Yang, J; Yuan, J 
2007 
Yes 
Analytica Chimica Acta
ISSN: 0003-2670
EISSN: 1873-4324 
591 
1 
123-131 
English 
17456433 
WOS:000246498900018 
A new spectrophotometric titration method coupled with chemometrics for the simultaneous determination of mixtures of weak acids has been developed. In this method, the titrant is a mixture of sodium hydroxide and an acid-base indicator, and the indicator is used to monitor the titration process. In a process of titration, both the added volume of titrant and the solution acidity at each titration point can be obtained simultaneously from an absorption spectrum by least square algorithm, and then the concentration of each component in the mixture can be obtained from the titration curves by principal component regression. The method only needs the information of absorbance spectra to obtain the analytical results, and is free of volumetric measurements. The analyses are independent of titration end point and do not need the accurate values of dissociation constants of the indicator and the acids. The method has been applied to the simultaneous determination of the mixtures of benzoic acid and salicylic acid, and the mixtures of phenol, o-chlorophenol and p-chlorophenol with satisfactory results. 
spectrophotometric titration; mixture of weak acids; principal component regression