BIO-360 BIOCHEMISTRY LABORATORY II
• VIII. WEEK
8th WEEK
QUANTITATIVE ESTIMATION OF
CARBOHYDRATES
8th WEEK
Carbohydrate determination by
3,5 Dinitro salicylic acid method
(theory)
8th WEEK
Carbohydrate determination by
Dubois method (theory)
8th WEEK
Carbohydrate determination by
3,5 Dinitro salicylic acid method
(application)
8th WEEK
Carbohydrate determination by
Dubois method (application)
3,5 Dinitro salicylic acid method
The DNSA method was first described by Sumner et al. (1921).
The method is based on the
oxidation of a reducing sugar with
3,5-dinitrosalicylic acid.
3,5 Dinitro salicylic acid method
This method tests the presence of
free carbonyl groups (C = O) in
reducing sugars.
However, with the functional
aldehyde group in glucose,
oxidation of functional ketone
groups of fructose and
simultaneous reduction of 3,5-
dinitrosalicylic acid to 3-amino-
5-nitrosalicylic acid under
alkaline conditions are also
involved.
3,5 Dinitro salicylic acid method
https://de.wikipedia.org/wiki/3,5-Dinitrosalicyls
%C3%A4ure
Carbohydrate determination by Dubois method
Total carbohydrate content can be
determined quickly by phenol-sulfuric acid
method.
Carbohydrate determination by Dubois method
This method, also known as the phenol-sulfuric acid method, can be used to determine the concentrations of all monomeric, oligomeric and polymeric carbohydrate samples according to the glucose standard. The resulting colored complex gives a maximum absorbance at 490 nm.
