Thin-Layer-Chromatography-TLC---pptx......

Thin Layer Chromatography is a technique used to isolate non-volatile mixtures. The experiment is conducted on a sheet of aluminium foil, plastic, or glass which is coated with a thin layer of adsorbent material. The material usually used is aluminium oxide, cellulose, or silica geg

1. Introduction to Thin Layer Chromatography (TLC) Thin Layer Chromatography (TLC) is a powerful analytical technique used to separate, identify, and purify a wide range of chemical compounds. It involves the separation of a mixture on a thin, stationary layer of adsorbent material, allowing for the visualization and analysis of individual components.

2. Principles of TLC 1 Adsorption Compounds separate based on their relative affinities for the stationary phase and the mobile phase. 2 Capillary Action The mobile phase travels up the stationary phase through capillary action, carrying the sample components with it. 3 Differential Migration Different compounds move at different rates, resulting in the separation of the components.

3. Stationary Phase Selection Adsorbent Materials Common stationary phases include silica gel, alumina, and cellulose. The choice depends on the polarity and chemical properties of the analytes. Plate Formats TLC plates are available in different formats, such as pre-coated, ready-to-use plates or plates that can be manually coated with the desired adsorbent. Plate Dimensions Plate size and shape can be selected based on the separation requirements and the available instrumentation.

4. Mobile Phase Considerations Solvent Polarity The mobile phase polarity is chosen to optimize the separation of the target compounds based on their polarity. Solvent Mixtures Binary or ternary solvent systems are often used to fine-tune the selectivity and elution order of the analytes. Optimization The mobile phase composition is carefully optimized through experimentation to achieve the desired separation and resolution.

5. Sample Preparation and Application 1 Sample Extraction The analytes are extracted from the sample matrix using appropriate solvents or techniques. 2 Sample Concentration The extracted sample may be concentrated to enhance the detection of the target compounds. 3 Sample Application The prepared sample is applied to the TLC plate as a small, concentrated spot or band using a micropipette or capillary tube.

6. Developing the TLC Plate Plate Equilibration The TLC plate is placed in a sealed chamber containing the mobile phase, allowing the solvent to equilibrate. Solvent Migration The mobile phase travels up the plate by capillary action, carrying the sample components along with it. Separation Occurs The individual components of the sample separate based on their relative affinities for the stationary and mobile phases.

7. Visualization and Detection UV Visualization Compounds with chromophores can be detected under UV light, which causes them to fluoresce. Staining Reagents Chemical reagents can be used to visualize non-fluorescent compounds by forming colored or fluorescent derivatives. Instrumental Detection Specialized detectors, such as densitometers, can quantify the separated compounds for further analysis.

8. Applications and Limitations of TLC Applications Limitations - Qualitative and quantitative analysis
- Purification and isolation of compounds
- Monitoring reactions and separations
- Identification of unknown substances - Limited separation efficiency compared to other chromatographic techniques
- Potential for poor reproducibility due to variable experimental conditions
- Difficulty in automating and quantifying the results

9. CONCLUSION