Page 28 - Phytochemistry -1 (PG404) / Clinical Pharmacy 2nd level students ( 2019 )

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

10 ml Fehling's solution = 0.05 g. glucose (monosaccharide)

ml of sugar solution taken = Accurate E.P.

0.2 = volume of sugar consumed by methylene blue to be reduced (4

drops)

B. For disaccharide

0.08 x 100

% of Maltose =

ml of sugar solution taken (E.P) - 0.2

10 ml Fehling's solution = 0.08 g. maltose red. Disaccharide

ml of sugar solution taken = Accurate E.P.

0.2 = volume of sugar consumed by methylene blue to be reduced (4
drops)

2. Estimation of Aldoses lodometrically

Principle

lodometric method is based on the fact that iodine can oxidize aldoses in
alkaline medium, whereas it has no effect on ketoses. I 2 oxidizes glucose

in alkaline medium into gluconic acid

C6H12O6 + 3KOH + I2 C6H11O6OK + 2KI + 2H2O

Procedure

1. measure 25 ml of the sugar solution in a stoppered flask and add a
considerable excess of 0.01 N iodine solution (20 ml by a pipette) and 5
ml of normal sodium carbonate solution or 40 ml of 0.1 N potassium
hydroxide solution. Allow the stoppered bottle to stand in the dark for 20

minutes.

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