Application of diffusion ordered-¹H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages

This work focuses on a quantitative analysis of sucrose using diffusion ordered-quantitative ¹H-nuclear magnetic resonance spectroscopy (DOSY-qNMR), where an analyte can be isolated from interference based on its characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of sucrose in deuterium oxide at 30 °C was 4.9 × 10^-10m²/s at field gradient pulse from 5.0 × 10^-2to 3.0 × 10^-1T/m, separated from other carbohydrates (glucose and fructose). Good linearity (r²= 0.9999) was obtained between sucrose (0.5-20.0 g/L) and the resonance area of target glucopyranosyl-α-C1 proton normalised to that of cellobiose C1 proton (100.0 g/L, as an internal standard) in 1D sliced DOSY spectrum. The DOSY-qNMR method was successfully applied to quantify sucrose in orange juice (36.1 ± 0.5 g/L), pineapple juice (53.5 ± 1.1 g/L) and a sports drink (24.7 ± 0.6 g/L), in good agreement with the results obtained by an F-kit method.