May 20, 2024

Purity of the precipitate: co-precipitation in Gravimetric analysis

Purity of the precipitate: co-precipitation in Gravimetric analysis

In gravimetric analysis, the purity of the precipitate is an important factor that can affect the accuracy and precision of the analysis. Co-precipitation is a common problem in gravimetric analysis that can lead to impurities in the precipitate, resulting in inaccurate results.

Co-precipitation occurs when impurities are carried down with the precipitate during the precipitation process. This can happen when the impurities are adsorbed on the surface of the precipitate or incorporated into the crystal lattice of the precipitate. Co-precipitation can occur due to various reasons such as incomplete precipitation, slow precipitation, use of reagents of low purity, or presence of interfering substances in the sample.

To minimize co-precipitation, several precautions can be taken during the precipitation process. These include:

  1. Preparing the sample in a way that minimizes the presence of impurities.
  2. Using a reagent of high purity and concentration to ensure complete precipitation.
  3. Adjusting the pH of the solution to ensure optimum conditions for precipitation.
  4. Adding the precipitating agent slowly and with constant stirring to ensure uniform precipitation.
  5. Allowing sufficient time for the precipitate to settle and form a compact layer before decanting the supernatant.
  6. Washing the precipitate with an appropriate solvent to remove any adsorbed impurities.
  7. Drying the precipitate at the appropriate temperature to remove any remaining moisture.

In addition, co-precipitation can be minimized by using a suitable co-precipitant that forms a stable compound with the impurities and prevents them from being carried down with the precipitate. This technique is known as selective co-precipitation.

Overall, the purity of the precipitate is crucial for accurate gravimetric analysis, and co-precipitation should be minimized through careful sample preparation and precipitation techniques.

First Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise

F Y B Pharm Sem-IF Y B Pharm Sem-II
BP101T Human Anatomy and Physiology I TheoryBP201T Human Anatomy and Physiology II – Theory
BP102T Pharmaceutical Analysis I TheoryBP202T Pharmaceutical Organic Chemistry I Theory
BP103T Pharmaceutics I TheoryBP203T Biochemistry – Theory
BP104T Pharmaceutical Inorganic Chemistry TheoryBP204T Pathophysiology – Theory
BP105T Communication skills TheoryBP205T Computer Applications in Pharmacy Theory
BP106RBT Remedial BiologyBP206T Environmental sciences – Theory
BP106RMT Remedial Mathematics TheoryBP207P Human Anatomy and Physiology II Practical
BP107P Human Anatomy and Physiology PracticalBP208P Pharmaceutical Organic Chemistry I Practical
BP108P Pharmaceutical Analysis I PracticalBP209P Biochemistry Practical
BP109P Pharmaceutics I PracticalBP210P Computer Applications in Pharmacy Practical
BP110P Pharmaceutical Inorganic Chemistry Practical
BP111P Communication skills Practical
BP112RBP Remedial Biology Practical

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