Barfoed's test reaction is based on the reduction of cupric acetate by reducing monosaccharides and reducing disaccharides. Reduction of cupric acetate produces cuprous oxide which gives a brick red precipitate.

Application

The aldehyde group of the monosaccharide which normally forms a cyclic hemiacetal is oxidized to the carboxylate. A number of other substances, including sodium chloride,[3] may interfere.

Technical Specification