400 MHz 1H nuclear magnetic resonance (NMR) spectroscopy was used in the context of food surveillance to control the regulatory limits of selected constituents of energy drinks. The preparation of the samples required only degassing, addition of 0.1 % of TSP in D2O for locking and referencing and phosphate buffer (pH 4.0) for chemical shifts adjustment. The quantification of caffeine, glucuronolactone, taurine and inositol was simultaneously possible using external calibration curves and applying TSP as internal standard. The applicability of the method was proven by analysis of 73 samples of energy drinks. The average caffeine concentration was 0.30 g/L, which is below the maximum limit of 0.32 g/L.
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