Journal of Electroanalytical Chemistry, Vol.826, 133-141, 2018
A comparative application of two-way and three-way analysis to three-dimensional voltammetric dataset for the pK(a) determination of vanillin
Two-way and three-way data analysis methods, multivariate curve resolution-alternating squares (MCR-ALS) and parallel factor analysis (PARAFAC) were applied to the potential-frequency dataset to estimate the pKa value of vanillin, used as a flavoring agent in foods and pharmaceuticals. Three-dimensional (3-D) voltammetric plots of vanillin at 12 different pHs in the range of 1.3-12.0 and 8 different frequencies in the range of 5-120 Hz were recorded as a function of potential (mV) and frequency (Hz) using square wave voltammetric (SWV) technique. The data matrix and data array of the 3D-voltammetric plots were processed by MCR-ALS and PARAFAC algorithms to predict the pKa values of the relevant flavor agent. In both MCR-ALS and PARAFAC approaches, the relative concentration profiles with the used pH range were used for the determination of the pKa without using extra additional software. In the MCR-ALS and PARAFAC applications, the numerical values for the pKa value of vanillin were computed as 7.91 and 7.97, respectively. The experimental results showed that the SWV technique coupled with the MCR-ALS and PARAFAC approaches have proved to be a quite promising solution to the problem of the chemometric evaluation the pKa of the compound of interest.
Keywords:Multivariate curve resolution-alternating least squares;Parallel factor analysis;Three-dimensional voltammogram;pKa determination;Vanillin