1.2.1.3 Urea spot test
Procedure
A) Weigh 2.5 g urease powder with small amount of distilled water, stir into paste and dilute to 50 ml with distilled water.
B) Rub 0.15 g bromothymol blue indicator powder in mortar with 2.4 ml 0.1 N NaOH (Sodium Hydroxide) solution. After indicator dissolves, wash mortar and pestle with distilled water and dilute to 50 ml with distilled water. Solution should be green; pH approx. 7.0.
C) Mix solution (A) and (B) in equal proportion.
Take 90 ml mixture solution of (C) and mix with 10 ml glycerol.
Pour mixture into watch glass. Dip pieces of heavy filter paper in solution.
| Allow to dry papers in a place free from NH |
Paper should be orange when dried. fumes, strong air currents or heat
Testing
Make strips of these papers and store in amber coloured glass bottle in a cool place.
Dissolve small quantity of feed/ feed ingredients with distilled water in a beaker. Deep the strip in a beaker and allow to dry it.
Appearance of blue colour indicates the presence of urea.
