engleski

Validation of potentiometric method for rapid reducing sugars determination in wine

The most common reducing sugars in grape and wine are glucose and fructose. Today, most methods used for determination of reducing sugars are based on the oxidation of carbonyl groups. Many of these methods are demanding in terms of the chemicals required, they involve several steps and thus much manual work, and they exhibit a lack of results reliability. The aim of this work was to develop a simple, reliable, sensitive, automated and repeatable method for determination of reducing sugars in wines. Method usefulness was tested by application to different wine samples (red, rosé, and white). To demonstrate that method of choice is suitable for its intended purpose, appropriate experimental work was designed to provide validation parameters: accuracy, precision and linearity. The obtained results showed that method is accurate at 1.1 % of average RSD for standard glucose solution. Accuracy of the method was proved by long term comparison of reference method and potentiometric method in wide range of concentration (0.5-147 g/L). The results obtained by proposed method are highly comparable with those obtained by reference method (r=0.9875 for range 0.5-14.2 g/L ; r=0.9856 for range 15.7-147 g/L). Obtained results showed high level of precision of method (3 and 3 % average RSD for repeatability of measurement and standard solution preparation, respectively). The linearity of the method was demonstrated (r=0.9985). The proposed method was simple and rapid because no previous treatment of the sample was required (only activated charcoal in case of red wine) for measurement and data were automatically recorded. The method has been successfully applied to wine routine analysis.

validation; potentiometry; reducing sugars; wine

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