A validated NMR method for the quantitative determination of rebaudioside A in commercial sweeteners

In recent years, the demand for rebaudioside A (Reb A) in the food industry has increased due to its sweetening power and organoleptic properties. Currently, there is a large variety of food products on the market for human consumption containing Reb A, and among them, sweeteners stand out. In the present work, a strategy for the quantification of Reb A in commercial sweeteners using quantitative H-1 nuclear magnetic resonance (qHNMR) with an external standard method applying the pulse length-based concentration determination (ERETIC2) is described. The developed qHNMR method notably satisfies the validation parameters, such as linearity, precision, accuracy, reproducibility, robustness, limit of detection, and limit of quantification (LOQ). The lineal range was established between 0.3-14.8 mM. The LOQ (0.3 mM) was sufficiently low to assess the quantification of Reb A in analysed samples. Intraday and intermediate precision were evaluated in different matrices and the percent relative standard deviation (%RSD) founded were lower than 1.93, and 2.79, respectively. Additionally, this qHNMR procedure has advantages such as a fast analysis time, easy sample preparation and low generation of solvent waste, which represents an environmentally responsible analytical alternative for the determination of Reb A in commercial sweeteners.