Page 36 - Phytochemistry -1 (PG404) / Clinical Pharmacy 2nd level students ( 2019 )

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

ESTIMATION OF A MIXTURE OF GLUCOSE and MALTOSE

Principle of assay:

Each of the glucose and also maltose reduces Fehling's solution before
hydrolysis (inversion). "The result of titration following the copper

reduction method gives the amount of glucose corresponding to the
reducing power of glucose and maltose before hydrolysis. If we hydrolyze
a known volume of sugar solution and a second titration is made, the result

obtained will represent the amount of glucose corresponding the glucose
originally present plus the glucose obtained from the hydrolysis of maltose.
The difference between the two amounts will be due to the glucose
obtained from the hydrolysis of maltose.

C12H22O12 + H2O 2C6H12O6

Maltose Glucose

342 g 2 X 180 g

i.e. 1 g Maltose will give 360/342 = 1.05 g glucose

As 1 g of Maltose, has the same reducing power as 0.62 g, of glucose, it

follows that 1 g of maltose after hydrolysis gives an increased reducing
power which is:

1.05 – 0.62 = 0.43 g glucose.

Each 1 g maltose gives an increase of 0.43 g. glucose.

1 g glucose = 1/0.43 gm maltose.

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