LAB EXPERIMENT 1___ _______
Calorimetric Determination of
Calorimetric Determination of
Glucose
Glucose
by the 3,5-dinitrosalicylic acid Method.
by the 3,5-dinitrosalicylic acid Method.
Principle :
Several reagents have been employed which assay sugars by using their
reducing properties. This method tests for the presence of free carbonyl
group (C=O), the so-called reducing sugars. This involves the oxidation
of the aldehyde functional group present in, for example, glucose and the
ketone functional group in fructose. Simultaneously, 3,5-dinitrosalicylic
acid (DNS) is reduced to 3-amino-5-nitrosalicylic acid under alkaline
conditions, as illustrated in the equation below :
The chemistry of the reaction is complicated since standard curves do not
always go through the origin and different sugars give different color
yields. The method is therefore not suitable for the determination of a
complex mixture of reducing sugar.
Materials
Materials
:
:
1 .Standard Glucose Solution:
0.1g anhydrous glucose is dissolved in distilled water and then raised the
volume to 100 ml with distilled water.
