Simultaneous determination of tartrazine and auramine O using FTIR spectroscopy and partial least square

Abstract

Nowadays, the use of colouring agents are needed to increase customers’ acceptability of foods. However, the development of food technology averts a big opportunity to use prohibited food colouring agents. Tartrazine (TAR) and Auramine O (AO) are two colouring agents may be used as food colorants. TAR is allowed, while AO is not allowed to be used in food colorants, respectively. For this study, the goal was to validate and apply Fourier transform infrared (FTIR) combined with multivariate calibrations for quantitative analysis of TAR and AO in beverages. An attenuated total reflectance FTIR scan of samples was performed at wavenumbers ranging from 4000-650 cm-1 . Quantitative analysis using FTIR spectroscopy was made by plotting the actual levels of TAR and AO obtained using HPLC and the prediction levels facilitated by partial least square (PLS) from the sample series. Internal cross-validation is performed on the model using the leave-one-out method. The root mean square error of prediction (RMSEP), the root mean square error of cross validation (RMSECV), the root mean square error of calibration (RMSEC), as well as the coefficient of determination (R2 ) become validation criteria. The results exhibited that calibration model was gained using variables of FTIR spectra at wavenumbers of 1730-1264 cm-1 . Correlation coefficients (r) of 0.9437 (TAR) and 0.9381 (FTIR) are present in the calibration model for the correlation of actual and predicted values. The method for analyzing tartrazine and auramine O in powdered beverages was validated using multivariate PLS FTIR calibration spectroscopy. FTIR spectroscopy could be further developed as an alternative technique for analysis of TAR and AO in beverages.