Page 32 - Phytochemistry -1 (PG404) / Clinical Pharmacy 2nd level students ( 2019 )

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

Ab Sample

% glucose = X 100 X 100 = mg % glucose

Ab Standard

Estimation of Non-reducing Sugars

Estimation of sucrose (cane sugar)

Principle:

The non-reducing sugars and also the polysaccharides do not reduce
Fehling's solution and therefore are not assayed as, such, but they are first

hydrolyzed by an acid and the liberated monosaccharaides are estimated
by one of the fore mentioned methods.

Procedure

1. Take 20 ml of the sugar solution by means of a pipette in a conical

flask. Add 5 ml of normal hydrochloric acid. Heat on a water bath for 15
min at 70° C

2. Add gradually sodium carbonate powder in small amounts until

effervescence ceases to neutralize the solution.

3. Transfer to a 100 ml measuring flask and wash the conical flask several

times with distilled water, adding the washings to the measuring flask and
complete with distilled water up to the mark.

4. Fill the burette with some of this solution of invert sugar and titrate

against Fehling's solution following the fore mentioned copper reduction
method.

5. Calculate the percentage of sucrose in the sample.

Calculations

10 ml of Fehling's solution= 0.05 g of invert sugar (glucose+ fructose).
Each l g of invert sugar originates from 0.95 g of sucrose.

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