Ronkart Sébastien N, Paquot Michel, Fougnies Christian, Deroanne Claude, Van Herck Jean-Claude, Blecker Christophe
Department of Food Technology, Gembloux Agricultural University, Passage des Déportés, 2, B-5030 Gembloux, Belgium; Department of Industrial Biological Chemistry, Gembloux Agricultural University, Passage des Déportés, 2, B-5030 Gembloux, Belgium.
Talanta. 2006 Dec 15;70(5):1006-10. doi: 10.1016/j.talanta.2006.02.024. Epub 2006 Mar 23.
A new sample preparation method for the water content determination of inulin by volumetric Karl Fischer (KF) titration was developed and compared to the usual method of introducing the sample directly in the methanol-based working medium, modified or not by formamide (1:3, v/v) in order to increase sample solubility. In the proposed method, inulins were externally prepared by dissolving them in pure formamide (2.5:7.5, w/w). The time of analysis of the liquid/liquid reaction of the new method between the dissolved sample and the reaction medium is about 1-2min, while the usual KF method is stopped after the 10min delay time. The developed method permits the determination of water included in the crystals of the sample, confirmed by analysing both crystalline and amorphous inulin samples. Another advantage of this new method is its applicability for the water content determination of other polysaccharides that are not readily soluble in the working medium. Moreover, water content determination can be done by any type of volumetric KF titrator, as this proposed technique is not dependent on any additional tools such as a built-in homogeniser or a heatable titration beaker.
开发了一种通过容量卡尔费休（KF）滴定法测定菊粉水分含量的新样品制备方法，并将其与通常的方法进行比较，通常方法是将样品直接引入基于甲醇的工作介质中，该介质可通过或不通过甲酰胺（1:3，v/v）进行改性以提高样品溶解度。在所提出的方法中，菊粉通过将其溶解在纯甲酰胺（2.5:7.5，w/w）中外加制备。新方法中溶解样品与反应介质之间的液/液反应分析时间约为1-2分钟，而通常的KF方法在延迟10分钟后停止。所开发的方法可以测定样品晶体中所含的水分，通过分析结晶型和无定形菊粉样品得到了证实。这种新方法的另一个优点是它适用于测定其他不易溶于工作介质的多糖的水分含量。此外，水分含量测定可以通过任何类型的容量KF滴定仪进行，因为该提议的技术不依赖于任何额外的工具，如内置均质器或可加热滴定烧杯。
