Difference Between Partition and Adsorption Chromatography
Partition Chromatography is essential in chemistry and helps students understand various practical and theoretical applications related to this topic. It is especially important in learning about separation techniques, mixture analysis, and how chemical substances interact with different phases. Students preparing for chemistry exams or real-life lab work frequently encounter this topic.
What is Partition Chromatography in Chemistry?
A partition chromatography refers to an analytical separation technique where the components of a mixture are distributed between two immiscible liquid phases. This concept appears in chapters related to chromatography, separation methods, and chemical analysis, making it a foundational part of your chemistry syllabus.
Principle of Partition Chromatography
The principle of partition chromatography is based on the difference in solubility (or partition coefficient, K) of the components of a mixture between the stationary phase (a liquid held on a solid support) and the mobile phase (another liquid that moves). Each compound distributes itself between these two phases according to its affinity, leading to separation.
The partition coefficient (K) is expressed as:
K = (Concentration of solute in stationary phase) / (Concentration of solute in mobile phase)
Compounds with a higher affinity for the stationary phase move slower, while those with a greater affinity for the mobile phase move faster.
Stationary and Mobile Phases in Partition Chromatography
| Phase | Description | Examples |
|---|---|---|
| Stationary Phase | A thin liquid layer supported on a solid substrate (e.g., water trapped in cellulose fibers of paper in paper chromatography). | Water on paper, liquid on silica gel |
| Mobile Phase | An immiscible liquid that moves through or over the stationary phase and carries the compounds with it. | Methanol, acetone, or other organic solvents |
Types of Partition Chromatography
- Paper Chromatography – Uses cellulose paper as the stationary phase with water as the immobile liquid. Very popular in schools and labs.
- Column Chromatography (liquid-liquid) – Stationary phase is a liquid coated on solid support inside a column; the mobile phase flows through by gravity.
- Thin Layer Chromatography (TLC), Liquid-Liquid Type – In some cases, stationary phase is a uniform thin liquid layer.
- High-Performance Liquid Chromatography (HPLC) – Advanced, uses high pressure and fine liquid stationary phase on a column.
Diagram and Stepwise Procedure of Partition Chromatography
Below is a typical setup and the procedure for paper chromatography,
- Place small drops of the sample mixture on the line using a capillary tube.
- Hang the paper so that its lower edge just touches the mobile phase (solvent) in a chamber, but not the samples.
- Cover the chamber and let the solvent rise by capillary action. Components partition between water (in cellulose) and the rising solvent.
- Remove the paper when the solvent front nears the top, and mark the front immediately.
- Visualize the separated spots (use UV light if colorless), calculate Rf values if needed.
Examples and Applications of Partition Chromatography
The most well-known example of partition chromatography is paper chromatography, often used for:
- Identifying components of inks, dyes, or plant pigments.
- Analyzing amino acids or nucleic acids in a mixture.
- Testing drug purity and detecting adulterants.
- Forensic examination of crime samples.
- Qualitative and quantitative separation in biochemical labs.
Modern techniques like HPLC and paper chromatography use the partition principle for accurate analysis of pharmaceuticals, food, beverages, and biological samples.
Difference Between Partition and Adsorption Chromatography
| Feature | Partition Chromatography | Adsorption Chromatography |
|---|---|---|
| Basis of Separation | Liquid-liquid partitioning | Liquid-solid adsorption |
| Stationary Phase | Liquid (held on a solid) | Solid |
| Examples | Paper chromatography, some HPLC types | Column chromatography, TLC (silica gel) |
| Mechanism | Solubility differences | Surface adhesion differences |
Relation with Other Chemistry Concepts
Partition chromatography is closely related to topics such as chromatography, adsorption chromatography, and types of chromatography, helping students build a clear understanding of separation techniques used in analytical and practical chemistry.
Try This Yourself
- Explain why water is considered the stationary phase in paper chromatography.
- Name two real-life uses of partition chromatography in the medical field.
- Draw and label the setup for a simple paper chromatography experiment.
Lab or Experimental Tips
Remember: When performing paper chromatography, always use a pencil (not ink) to draw the baseline. Mobile phase selection is crucial—choose a solvent in which the substances of interest are soluble but the stationary phase is not washed away. Vedantu educators use easy analogies in their live classes to help memorize the flow of phases: "stationary stays, mobile moves!"
Final Wrap-Up
We explored partition chromatography—its definition, principle, diagram, uses, and comparisons with other techniques. This knowledge helps in a variety of scientific, industrial, and everyday applications. For further study, live classes and easy-to-read notes on Vedantu provide more tips for mastering chromatography topics.
Related Vedantu Resources
FAQs on Partition Chromatography Explained: Principle, Types & Applications
1. What is partition chromatography?
Partition chromatography is a separation technique in Chemistry that divides the components of a mixture between two immiscible liquid phases. Each compound moves depending on its solubility in the stationary and mobile phases.
2. What is the principle of partition chromatography?
Partition chromatography works on the distribution ratio or partition coefficient principle. Separation occurs because compounds have different solubilities in two liquid phases:
- One phase is stationary (often water or another liquid immobilized on a solid support).
- The other is a mobile phase (another immiscible liquid moving over or through the stationary phase).
- Each component partitions based on its affinity for these phases, leading to differential migration and separation.
3. Which is the stationary phase in partition chromatography?
The stationary phase is a thin film of liquid (usually water or another polar liquid) that is immobilized or coated on an inert solid surface (such as cellulose in paper chromatography).
4. Which is the mobile phase in partition chromatography?
The mobile phase is an immiscible solvent (such as an organic liquid) that moves through or over the stationary phase, carrying components of the mixture at different rates based on solubility.
5. What are examples of partition chromatography?
Common examples of partition chromatography include:
- Paper chromatography (water as stationary phase, organic solvent as mobile phase)
- Liquid-liquid column chromatography
- Separations of amino acids, dyes, and inks
6. What are the types of partition chromatography?
Major types include:
- Paper chromatography
- Liquid-liquid column chromatography
- Gas-liquid chromatography (variation involving gas mobile phase)
7. Is TLC (Thin Layer Chromatography) a partition chromatography?
TLC (Thin Layer Chromatography) can act by both partition and adsorption mechanisms, depending on the stationary phase used. Most commonly, TLC operates on adsorption principles, but partition effects are also observed in some setups.
8. Is HPLC a type of partition chromatography?
HPLC (High-Performance Liquid Chromatography) may use partition as the primary separation mechanism in reverse-phase or liquid-liquid columns. HPLC can be adapted for both partition and adsorption depending on column filling and solvent used.
9. How does partition chromatography differ from adsorption chromatography?
The key differences include:
- Partition chromatography: Separation is based on differential solubility of components between two liquid phases.
- Adsorption chromatography: Separation is based on the adhesion (adsorption) of molecules to a solid stationary phase.
- Stationary phase: Liquid film in partition, solid in adsorption.
10. What determines the movement rate of substances in partition chromatography?
The rate of movement depends on each compound’s partition coefficient (ratio of solubility in stationary vs. mobile phase). The higher the affinity for the stationary phase, the slower the movement.
11. Why is paper chromatography most suitable for colored compounds?
Pigmented or colored substances allow for easy visualization of separated spots as they migrate on the paper. This helps clearly illustrate the partitioning and separation process.
12. Can partition and adsorption mechanisms occur together in chromatography?
Yes, some chromatographic techniques, such as TLC and HPLC, may show both partition and adsorption effects depending on the phases and solvents used in the process.
