Amino acids electrochemical determination by handmade ceramic Sonogel-Carbon devices: Resolution of the tyrosine and tryptophan system signal overlapping by chemometric tools

Abstract

Handmade carbon black and polyaniline-modified Sonogel-Carbon electrodes were applied for the electroanalytical determination of tyrosine and tryptophan, achieving significant improvements with respect to unmodified sensors. Higher peak current intensity and anti-fouling properties were observed and, consequently, better analytical figures of merits were obtained after the calibrations. The interference effect of several amino acids in these applications was assessed as negligible. Recovery values ranging from 101 to 107% were obtained in the determination of these analytes in real food supplement samples. Finally, several chemometrics techniques were used to resolve the severe signal overlapping of the tyrosine/tryptophan system. Linear discriminant analysis (LDA) was able to discriminate between samples containing each amino acid or both of them, and principal component analysis (PCA) and partial least squares regression (PLS) techniques were able to quantify the amount of each amino acid present in the samples.