Detection of lead
DETECTION OF LEAD /strong>
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Aim
- To detect the presence of lead in the given sample (Grunwald test)
Principle
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The determination of lead in biological material is done by wet digestion.
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Nitric acid is used to digest the organic matter.
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Addition of potassium iodide imparts yellow colour due to formation of lead iodide.
Materials
- Conc. Nitric acid.
- 10% potassium iodide solution.
- Test tube and spirit lamp.
Procedure
Inference
- Development of yellow colour indicates the presence of lead.
Test
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Procedure
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Inferences
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Test1
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1 ml of test solution + a drop of 10% ammonium carbonate
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Appearance of white colour / precipitate
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Test2
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1 ml of test solution + a drop of 20% ammonium sulfide
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Appearance of black colour
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Test3
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1 ml of test solution + a drop of 15% potassium iodide solution
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Appearance of bright yellow colour
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Last modified: Wednesday, 16 May 2012, 9:22 AM