Sugars are members of the carbohydrate family. Examples include glucose,
fructose and sucrose. Some sugars can act as reducing agents and these sugars
will contain an aldehyde functional group. This property can be used as a basis
for the analysis of reducing sugars. For example Fehling’s solution contains
copper (II) ions that can be reduced by some sugars to copper (I) ions. This
reaction can be used for the quantitative analysis of reducing sugars.