E Analytical Determination of Reducing Sugars

There have been very many methods suggested from time to time for the determination of reducing sugars, and considerable difficulty has been experienced in obtaining one which is sufficiently foolqxoof to give satisfactory results in the hands of all operators. In 1936 von Stieglitz and Home 11) reviewed several methods and recommended the electro* metric determmat~on of the end point with the EynowLane Method. In 1937 the International Commission for Uniform Methods of Sugar Analysis [2) received reports on three methods whi'ch appear to give good promise of their ability to eliminate or at least greatly reduce un. desirable features of the Soxhlett solutions used for the Eynon~Lane determination. For example, the effect of variations in the boiling period and reducing effect of sucrose are at least equally as important as the correct identification of the end-point. Also a single solution completely non.auto,reducing can be substituted for the two separate Soxhlett solutions and a larger volume is generally used for each titra, tion enabling more accurate measurement of the volume of reacting solution. The undesirable physical features of titrating a boiling soh, tion are also eliminated. There are perhaps two aspects which are some, times claimed in favour of the Eynon#Lane method viz. (1) relative sim, plicity of technique and (2) in the case of materials containing a large proportion of reducing sugars (such as final molasses) the welght of sample which can be used for analysis is larger for the Soxhlett solution. Each of these aspe,cts has been investigated and the results are recorded in this paper.