Tests for Carbohydrates

Test

Reagent

Purpose

Molisch
test

Molisch reagent
(alpha-napthol)

detect the presence of
carbohydrates

Iodine
test

Iodine solution

detect the presence of starch
(polysaccharide) in a sample

Benedict's
test

Benedict's reagent
[copper(II) sulfate, sodium
carbonate, and sodium citrate]

detect the presence of reducing sugars,
such as glucose and fructose

Barfoed's
test

Barfoed's reagent

used to differentiate between monosaccharides
and disaccharides (positive for monosaccharide)

Seliwanoff
test

Seliwanoff's reagent
(resorcinol and HCl)

used to differentiate between aldoses and
ketoses, specifically detecting ketose
sugars (positive for ketose sugar, eg. fructose)

Rothera
test

Sodium nitroprusside,
ammonium sulfate

detect ketone bodies (acetone,
acetoacetic acid, and beta-
hydroxybutyric acid) in urine