Quantitative Determination of Glucose and Five Steviol Glycosides from Stevia Rebaudiana and Related Products

Stevia rebaudiana Bertoni, a plant native to Paraguay and commonly known as sweetleaf, sugarleaf, or simply stevia, is a natural sweetener. Steviol-type diterpene glycosides are richly existed in S. rebaudiana leaves. As sweetener takes a role to substitute for sucrose/glucose in food and drinks, monitoring glucose in sweetener products is very important for quality assurance. An UPLC-UV-MS method is used for estimation of glucose from stevia products. Out of 35 tested samples, glucose was found from six products in the range of 0.9 – 91.5% (w/w). Moreover, with the aim of quantitative determination of steviol glycosides in S. rebaudiana and related products, an UPLC-UV-ELSD/MS method is developed for identifying rebaudioside A, stevioside, rebaudioside D, dulcoside A and steviolbioside from S. rebaudiana. The separation was achieved by using high strength silica type column material with a gradient system composed of water, acetonitrile, and formic acid. The method was validated and successfully applied for the analysis of stevia products.