Page 88 - Feed Lab

Suguna Management System Ver 1.0 / SOP / FQL / P2 - 14 Page 1 of 1

14. Estimation of Urease Activity (Phenol red)

with 0.1N sulphuric acid. It should be stored in
SCOPE
refrigerator.
To estimate the urease activity for Soya bean meal by
phenol red solution method. PROCEDURE
FTake a clean dried watch glass and place it on a
REAGENTS
white paper. Spread fine ground Soya sample on
F0.1N Sodium Hydroxide: Dissolve 0.4gmof the watch glass and it should be one layer.
Sodium Hydroxide AR grade in 100mldistilled (Picture - 1)
water).
FBefore using the phenol red solution for analysis it
F0.1N Sulphuric Acid: Dissolve0.3mlof Sulphuric should be amber colour .(If PRS is red colour then
acid AR grade in 100mldistilled water). add 0.1N suphuric acid drop wise till it changes to
amber colour OR if PR S is yellow colour then add
FUrea Phenol red solution(PRS): Dissolve 0.07 0.1N sodium hydroxide drop wise till it changes to
gm of phenol red power in 3.5 ml of 0.1N sodium amber colour.) ( Picture - 2)
hydroxide and add 17.5 ml of double distilled water
to the same solution in one beaker FAdd Phenol red solution drop wise to the sample on
the watch glass carefully and note the time.
FDissolve10.5gm of urea in 150mlof double distilled (Picture - 3)
water in another beaker. Mix these two solutions FThe time should be exactly 5 minutes. (Picture - 4)
together and titrate till it becomes amber coloured

Picture - 1 Picture - 2 Picture - 3 Picture - 4

CALCULATION
Measurement of urease activity in units=% of red particles/50(correction factor).
For e.g. : %of red particlesis5 in the sample then urease activity is 5 / 50 =0.1 units.

Prepared by : Approved by :
76 Director - Technical