By
Colour Development Method:
Reagents
required:
i) 3% Sodium Nitrite solution (3 gm of Sodium Nitrite in 100 ml
water )
ii) 1N HCl Solution ( 8.5 ml Hydrochloric acid in 100 ml water )
iii) 1N NaOH Solution ( 4 gm of Sodium Hydroxide in 100 ml Water)
Standard Solution : Take
100 mg of Paracetamol WS in 100 ml of volumetric flask, dissolved and make the
volume 100 ml with water. Take 5 ml of above solution in 50 ml of volumetric
flask and dilute to 50 ml with water. (100 mcg/ml)
Sample solution : Weigh 20
Capsules From a quantity of the mixed contents of 20 capsules take powder
equivalent to 100 mg of Paracetamol in 100 ml volumetric add 70-80 ml of water
and shake for one hour and dilute to 100 ml with water. Filter and take 5 ml of
above solution in 50 ml of volumetric flask and dilute to 50 ml with
water. (100 mcg/ml)
Procedure: Take 5 ml of sample and
standard solution; add 2 ml of 3% Sodium Nitrite solution in water and 1 ml of
1N Hydrochloric Acid. Mix and allow it to stand for 5 minutes add 3 ml of 1N
Sodium Hydroxide, Mix and allow it to stand for further 5 minutes. Dilute to 50
ml with water.
Take reading on suitable Spectrophotometer
at 450 nm using water as a blank.
Calculation
