Simultaneous determination of aspartame and acesulfame-K by molecular absorption spectrophotometry using multivariate calibration and validation by high performance liquid chromatography

A new method to determine mixtures of two sweeteners, aspartame and acesulfame-K, in commercial sweeteners is proposed. A classical 52 full factorial design for standards was used for calibration in the concentration matrix. Salicylic acid was used as internal standard in order to evaluate the adjustment of the real samples in the PLS-2 model. This model was obtained from UV spectral data, validated by internal cross-validation and was used to find the concentration of analytes in the commercial samples. The PLS-2 method was validated externally by high performance liquid chromatography (HPLC), finding, in all cases, a relative error of less than 10% between the PLS-2 and the HPLC methods. The mean value of recovery degree in real samples was 99.2% with standard deviation of 3.2%. The proposed procedure was applied successfully to the determination of mixtures of aspartame and acesulfame-K in artificial sweeteners.