Page 61 - Feed Lab

Suguna Management System Ver 1.0 / SOP / FQL / P2 - 02 Page 1 of 2

2. Estimation of Crude Protein – Micro

Kjeldhal Distillation

FConical flask, 250 ml
SCOPE
To estimate the crude protein in feed &feed stuffs by FReagent bottle, 1000 ml, 500 ml, 250 ml
Micro Kjeldhal distillation method.
FNi- Spatula
PRINCIPLE
REAGENTS
Sample is digested in sulphuric acid using copper
sulphate as catalyst and by adding sodium sulphate an FNitrogen free concentrated sulphuric acid, AR
hydrous to elevate the boiling point converting grade
organically bound nitrogen into ammonium sulphate FSodium Sulphate (anhydrous)
when heated with excess alkali, ammonia is liberated
which is distilled into known excess of saturated acid. FCupric Sulphate
The unreacted (unneutralized) acid is back titrated with F40%sodiumhydroxide w/v, AR grade
standard alkali. From titrated values the nitrogen
content and crude protein are calculated by multiplying F0.143N sodiumhydroxide (5.8 gm of sodium
by 6.25 (100/16). hydroxide in 1 litre of water), AR grade
F0.143 Nsulphuricacid (3.9 ml of sulphuric acid in 1
APPARATUS
litre of water), AR grade
FAnalytical Balance, 1 mg /0.1 mg accuracy
FMethylred indicator
FKjeldhal flask, 500 ml
FPhenolphthalein indicator.
FDigestion chamber
F0.1N Potassium Hydrogen Phthalate- 5.1055 gm /
FMicro Kjeldhal distillation assembly
250 ml of distilled water, AR grade
FVolumetric flask, 100 ml
BLANK
FBurette, 10 / 25 ml
FTake 5gm activated sodium sulphate + 0.5gm of
FPipette, 5 ml, 10 ml cupric sulphate and 25 ml of concentrated
sulphuric acid to the Kjeldhal flask and do digestion
FCylinder, graduated, 500 ml and distillation as per the crude protein procedure.

Prepared by : Approved by :
49 Director - Technical