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

DETECTION OF LEAD

Aim

• To detect the presence of lead in the given sample (Grunwald test)

Principle

• The determination of lead in biological material is done by wet digestion.
• Nitric acid is used to digest the organic matter.
• Addition of potassium iodide imparts yellow colour due to formation of lead iodide.

Materials and Chemicals

• Conc. Nitric acid.
• 10% potassium iodide solution.
• Test tube and spirit lamp.

Procedure

• Mince the liver / kidney piece or collect a small amount of scraping from stomach wall
• Add a four drops of concentrated nitric acid .
• Heat gently (avoid over heating) till the contents get dried.
• Add a few drops of water and two drops of 10% potassium iodide solution.

Inference

• Development of yellow colour indicates the presence of lead.

SPOT TEST FOR DETECTION OF LEAD

Aim

       To detect the presence of lead in biological material.

Test	Procedure	Inferences
Test1	1 ml of test solution + a drop of 10% ammonium carbonate	Appearance of white colour / precipitate.
Test2	1 ml of test solution + a drop of 20% ammonium sulfide	Appearance of black colour.
Test3	1ml of test solution + a drop of 15% potassium iodide solution	Appearance of bright yellow colour.