A rapid UHPLC-ELSD method for determination of glucose, fructose and sucrose in tomato

Soluble sugars are essential for tomatoes, and one of the important quality indicators in ripening fruit. In this study, a rapid and reliable method for detecting glucose, fructose, and sucrose in tomato was developed and validated using a ultra high-performance liquid chromatography with an evaporative light scattering detector (UHPLC-ELSD). The chromatographic separation was performed with Waters X Bridge BEH Amide column at 65 degrees C and the flow rate of 0.6 mL/min. The drift tube temperature was set at 40 degrees C, with a nitrogen pressure of 50 psi. The free sugar detection method demonstrated excellent linearity (30-1000 mu g/mL) for all tomato samples tested (leaves, ovary, fruitlet, and mature fruits from different cultivars), with R-2 = 0.9992-0.9999. The limits of detection (LOD) and quantitation (LOQ) for fructose, glucose and sucrose were 7.3, 8 and 8.6 mu g/mL and 30, 22 and 16 mu g/mL, respectively. The recovery rate ranged from 95 to 108 %. RSD of the recovery rate ranged from 0.7 to 1.4 %. Furthermore, the developed method demonstrated good intra-day and inter-day precision (RSD < 2 %). In conclusion, this novel sugar detection method can potentially be used to detect and quantify glucose, fructose, and sucrose concentrations in leaves, ovaries, fruitlets, and mature fruits of tomato within 6 min, which could also detect free sugars in fruits of apple, banana, grapefruit, strawberry, watermelon.