銅(II)-EDTAを用いる還元糖の間接滴定法

概要

論文の詳細を見る
The proposed method consists in heating of reducing sugar with a basic 0.1 M Cu(II)-EDTA solution, which is followed by titration of liberated EDTA without filtration. About 30 g of NaOH should be involved. in a liter of 0.1 M Cu(II)-EDTA (Fig. 2). If the heating is carried out in steam (Fig. 1), the reaction between Cu(II) and sugar is complete in 4 minutes, and longer heating does not affect the reagent blank (Fig. 4). Less than 30 mg of reducing sugar is determined with 10 mlof 0.1 M Cu(II)-EDTA solution. In the case of glucose, the equivalent mole ratio of Cu(II) and sugar is 4 : 1. EDTA is titrated potentiometrically in buffered borate medium of pH 9 with 0.1 M Ca2+ or Cu2+ standard solution, by employing the combination of either Ag electrode and Ag+ indicator or Hg electrode and Hg2+ indicator. The Ag method is affected by the presence of a large amount of Cu2O (corresponding to more than 10 mg of sugar) (Fig. 5), but the Hg method is not (Fig. 6). The potential break at the end point is larger in the Ag method. The standard deviation for 10 determinations is about 0.5%, and the time required for an analysis is about 10 minutes. Several of other reducing sugars are also determined in a similar way (Fig. 7).
社団法人日本分析化学会の論文