Synergy interval Partial Least Square (siPLS) with potentiometric titration multivariate calibration for the simultaneous determination of amino acids in mixtures

Abstract

The simultaneous determination of amino acids in solution is important for food and nutrient industries. This study investigated the feasibility of potentiometric titration with synergy interval Partial Least Square (siPLS) for the simultaneous determination of glycine, glutamic acid and phenylalanine in aqueous solution. The methods used were compared with the traditional Partial Least Square (PLS) that based on full pH range. The performance was evaluated by the Root Mean Square Error of Cross-Validation (RMSECV), the Root Mean Square Error of Prediction (RMSEP) and the correlation coefficient (R). By optimizing the pH region with siPLS, a good linear model was produced for the calibration set with correlation coefficient R of 0.9947, 0.9956 and 0.9913 for glycine, glutamic acid and phenylalanine, respectively. A single set of synergy mixtures was tested independently and good results were obtained. The results show that the siPLS method can locate the informative region by using a graphically-oriented interface which is more easily to use and interpret. The study proves the feasibility of potential titration with chemometrics in the simultaneous determination of amino acid mixtures without preliminary separation.