PLS-UV Spectrophotometric Method for the Simultaneous Determination of Ternary Mixture of Sweeteners (Aspartame, Acesulfame-K and Saccharin) in Commercial Products

Abstract Aspartame (Apt), Acesulfame-K (Ace-K) and Saccharin (Sac), low-calorie, high-potency artificial sweeteners are currently used in carbonated beverages, dietary food and drinks. Their increased application in food and drink products has given a new impetus to develop fast and accurate methods for their determination. Absorption spectra of Apt, Ace-K and Sac strongly overlap. Therefore a direct determination of these analytes in ternary mixture is impossible without a separation step. In order to overcome this difficulty partial least squares (PLS) method has been proposed.

In this work, a simple and fast analytical procedure is proposed for the simultaneous determination of Apt, Ace-K and Sac in commercial products (powder drinks and colored beverages). The sweeteners were extracted n-butanol solution and the absorption spectra were recorded between 190 – 300 nm against blanc solution and the absorbance values were taken 5 nm interval. The method involves the use of 27 standard mixtures of the three compounds assayed, considered at three concentration levels and measured of samples in 0.1 N H ₃PO₄ solution.

A calibration set containing between 7 – 9 μ.g mL⁻¹ of Apt, 1–3 μ.g mL⁻¹ of Ace-K, and 2–4 μ.g mL⁻¹ of Sac was used. The designed and optimized training set of calibration was applied to the determination of three sweeteners of several synthetic mixtures. The method was also applied to commercial drinks and satisfactorily results were obtained. The procedures do not require any separation step for colorless sample (powder drink), but only an extraction step for colored beverages (powder and liquid) was used. The effect of cyclamate (CA) and ascorbic acid (AA) was also investigated.