REACTIONS OF CARBOHYDRATES 1965 
Ethyl Acetate Reaction. Add a little sodium acetate and concen- 
trated sulphuric acid to the sample and heat. The fruity odor of ethyl 
acetate will be detected if alcohol was present in the sample. Quanti- 
tative methods for this may be obtained from chemical texts. 
Acetone. Iodoform Reaction. This is the same test as is used to 
detect ethyl alcohol except that it is carried out in the cold. Add to 
the same a few drops of sodium hydroxide and very slowly iodine- 
potassium-lodide solution until the solution is colored yellow. If acetone 
is present iodoform will settle out. 
Nitroprusside Test. Adda few drops of a freshly prepared solution 
of sodium nitroprusside and about 1 c.c. of sodium hydioxide. A red 
color is produced which will fade to a yellow on standing. 
Molisch Reaction. Add a few drops of Molisch reagent to the 
sugar solution in a test tube. Incline the tube and pour a few cubic 
centimeters of concentrated H2SO4 down the side of the test tube. A 
lavender color will be formed if sugars are present. If the H2SQOu 1s put 
into the test tube first, and the sugar-Molisch reagent mixture run in 
on top, a ring test may be observed. 
Seliwanoff’s Reaction for Ketoses. Add a small amount of the 
sugar or unknown solution to a few cubic centimeters of Seliwanoff’s 
reagent and heat to boiling. A reddish coloration indicates the presence 
of ketose sugars. 
Fehling’s Test. This depends upon the action of reducing sugars. 
This action is generally attributed to the presence of an aldehyde or 
ketone group. Some regard other parts of the sugar molecule as in- 
volved in this reduction. 
Two solutions are used in the test. These are kept apart until used. 
If they are mixed and allowed to stand, the copper will be slowly reduced 
by the tartrate. The solutions have the following composition: 
Solution I. 
Copper sulphate.... ..... . . 384 65 gms. 
Distilled water................ 500.00 c.c. 
Solution IT. 
Potassium hydroxide ......... 125 00 gms. 
Sodium potassium tartrate... .. 173 00 gms. 
Distilled water................ 500.00 c.c. 
In testing for reducing sugars, mix equal parts of these two solutions 
and heat to boiling. This will determine whether the solutions are good, 
If any copper is precipitated by this heating, the solutions must be dis- 
