Rapid Simultaneous Spectrophotometric Determination of Food Dyes in Soft Drink Using Continuous Wavelet Transform and Multivariate Calibration Methods

In this study, the spectrophotometric technique along with chemometrics methods have been developed for the simultaneous determination of Sunset Yellow (SY) and tartrazine (TZ) in mixtures and soft drinks without any prior separation or purification. The first method is the Continuous Wavelet Transform (CWT), in which various wavelet families were investigated. Eventually, the Gaussian wavelet family of the second order with a scaling factor of 5 for SY and the Daubechies wavelet families of the second order with a scaling factor of 64 for TZ were selected. Both dyes showed good linearity, with the coefficient of determination (R2) of 0.996 and 0.9981  for SY and TZ, respectively. The Limit of Detection (LOD) and Limit of Quantification (LOQ) values were 0.1794, 0.0003 𝜇g/mL, and 0.6066, 0.0983 𝜇g/mL for SY and TZ, respectively. On the other hand, multivariate calibration methods, including Partial Least Squares (PLS) and Principal Component Regression (PCR) were studied. The PLS recovery range was obtained from 100.06% to 103.06% and 100.86 to 103.49 for SY and TZ, respectively. Also, the mean recovery (%) of the PCR method was 101.41 and 102.90 for SY and TZ, respectively. In addition, values of RMSE related to the PLS and PCR were achieved 0.2578, 0.3023, and 0.2635, 0.5602 for SY and TZ, respectively. High-Performance Liquid Chromatography (HPLC) as a reference method was applied for the soft drink, and the results were compared with the proposed methods using a one-way analysis of variance (ANOVA). There was no significant difference between them.