VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

DETECTION OF CYANIDE IN THE GIVEN PLANT SAMPLE

Aim

• To detect the presence of cyanide in the given sample (sodium picrate paper test)

Materials and Chemicals

• Sodium bicarbonate
• Picric acid
• Filter paper
• Distilled water
• Chloroform
• Test tube and
• Spirit lamp

Preparation of Sodium Picrate Paper

• Dissolve sodium bicarbonate 5 g and picric acid 0.5g in 100 ml of distilled water.
• Cut the filter paper into strips of 2” x 6” size.
• Dip the strips in the reagent and dry in cool place.

Procedure

• Take the given sample in a test tube and add a few drops of water and chloroform
• Plug the test tube with cotton and hang the dried picrate paper inside the test tube
• The paper should not touch the fluid in the tube
• Heat the tube gently till fumes evolve
• Observe the colour of paper

Inference

• If the colour of paper changes from yellow to brown it indicates that the plant sample is positive for cyanide. (The leaves and stomach contents are to be frozen immediately after collection in polythene bag as CN is likely to evaporate).