What Are The Different Types Of Electrophoresis With Principle And Applications
Types of Electrophoresis is essential in chemistry and helps students understand various practical and theoretical applications related to this topic. This concept is widely used for separating biological molecules like DNA, RNA, and proteins in labs and research.
Let’s learn its principle, major types, step-by-step examples, and real-life application, all in a simple, student-friendly way.
What is Types of Electrophoresis in Chemistry?
A type of electrophoresis refers to a specific method used to separate charged particles or molecules under the influence of an electric field. This concept appears in chapters related to gel electrophoresis, separation techniques, and analytical chemistry.
It is a foundational part of your chemistry syllabus and is important for understanding how scientists analyze complex mixtures using electricity and gels or papers.
Molecular Formula and Composition
Electrophoresis is not a chemical compound, so it does not have a molecular formula. Instead, it is a process involving a sample (like DNA or proteins) in a supporting medium (such as agarose gel, polyacrylamide gel, paper, or capillary) and an electrolyte buffer. Its components vary depending on the type of electrophoresis performed.
Preparation and Synthesis Methods
To perform electrophoresis, first prepare the gel or paper, then mix your biological sample with a loading dye. Place the prepared medium in an electrophoresis chamber filled with buffer solution.
Load the sample in wells and apply a voltage. The procedure changes slightly depending on the type—gel electrophoresis (agarose or polyacrylamide), paper electrophoresis, or capillary-based methods.
Physical Properties of Types of Electrophoresis
Physical properties depend on the medium used:
- Agarose gels are semi-solid, porous, and transparent.
- Polyacrylamide gels are clear, can be soft or firm, and allow fine separation.
- Paper is flat, absorbent, and used for simple separations.
- Capillaries are thin tubes, usually made of glass or plastic.
Chemical Properties and Reactions
Electrophoresis does not cause chemical changes but analyzes molecules based on their physical — not chemical — properties. However, buffer may maintain pH or react with sample ends to stabilize molecules during migration. Sometimes, special stains are used after separation to visualize the bands.
Frequent Related Errors
- Confusing movement direction: cations move toward the cathode, anions toward the anode.
- Forgetting that different gels separate by different properties (size, charge, shape).
- Not choosing the correct buffer for the molecule studied.
- Running electrophoresis too long, causing samples to migrate out of the gel.
Uses of Types of Electrophoresis in Real Life
Types of electrophoresis are widely used in biotechnology labs for DNA fingerprinting, paternity testing, protein analysis, medical diagnostics, and quality control in drug manufacturing.
For example, agarose gel electrophoresis is crucial in molecular biology for checking DNA purity, while SDS-PAGE (a gel electrophoresis type) is used to separate proteins by size.
Relation with Other Chemistry Concepts
Electrophoresis is closely related to chromatography and electrolysis. Both are separation techniques but use different physical principles (chromatography separates by affinity, electrophoresis by charge/size). Understanding these methods helps students build strong analytical skills.
Step-by-Step Reaction Example
- Prepare an agarose gel with wells for sample loading.
Mix agarose powder with buffer, heat until dissolved, pour into tray, let it set. - Load DNA samples mixed with tracking dye into wells.
Use a micropipette for accuracy. - Connect chamber to power supply and switch on.
DNA migrates towards the positive (anode) as it is negatively charged. - Watch for blue dye movement to monitor progress.
- Stop power when bands are well separated. Remove gel and stain (e.g., with ethidium bromide).
- Visualize bands under UV light and compare to a DNA ladder marker.
Lab or Experimental Tips
Remember, always use fresh buffer and ensure gel thickness is even for best results. Place wells close to the negative terminal for nucleic acid runs, as nucleic acids migrate toward the positive end. Vedantu educators suggest drawing a simple set-up diagram to remember orientation and current flow.
Try This Yourself
- Name the three main types of electrophoresis based on support medium.
- Why is agarose preferred for DNA, but polyacrylamide for proteins?
- Write two real-life examples where electrophoresis is applied outside biology.
Final Wrap-Up
We explored Types of Electrophoresis—their principles, types, procedures, and significance in chemistry and biology. With clear steps and real-life examples, you’ll find this topic easier to remember for exams and lab work.
FAQs on Types Of Electrophoresis And Their Principles
1. What are the types of electrophoresis?
The main types of electrophoresis are techniques that separate charged particles based on their movement in an electric field through different media.
- Paper electrophoresis – uses filter paper as the support medium.
- Gel electrophoresis – uses agarose or polyacrylamide gels to separate DNA, RNA, or proteins.
- Capillary electrophoresis – performed in narrow capillary tubes for high-resolution separation.
- SDS-PAGE – separates proteins mainly by molecular weight.
- Isoelectric focusing (IEF) – separates proteins based on their isoelectric point (pI).
- Immunoelectrophoresis – combines electrophoresis with antigen–antibody reactions.
2. What is gel electrophoresis?
Gel electrophoresis is a laboratory technique that separates DNA, RNA, or proteins based on their size and charge using an electric field through a gel matrix.
- A gel (agarose or polyacrylamide) acts as a molecular sieve.
- Samples are loaded into wells in the gel.
- When voltage is applied, negatively charged molecules move toward the anode.
- Smaller molecules move faster and travel farther than larger ones.
3. What is the difference between agarose gel and polyacrylamide gel electrophoresis?
The main difference between agarose gel electrophoresis and polyacrylamide gel electrophoresis (PAGE) is the size range and resolution of molecules they separate.
- Agarose gel: Used mainly for separating large DNA or RNA fragments (100 bp to several kb); lower resolution.
- Polyacrylamide gel (PAGE): Used for smaller DNA fragments and proteins; higher resolving power.
- Agarose gels are easier to prepare, while PAGE provides sharper bands.
4. What is SDS-PAGE?
SDS-PAGE is a type of polyacrylamide gel electrophoresis that separates proteins based on molecular weight using sodium dodecyl sulfate (SDS).
- SDS is an anionic detergent that denatures proteins and gives them a uniform negative charge.
- Proteins are separated only by size, not shape or native charge.
- Smaller proteins migrate faster through the polyacrylamide gel.
5. What is capillary electrophoresis?
Capillary electrophoresis is a high-resolution separation technique in which charged particles migrate through a narrow capillary tube under a high electric field.
- The capillary is filled with an electrolyte buffer solution.
- Separation occurs based on charge-to-size ratio.
- It requires very small sample volumes.
- Detection is often done using UV or fluorescence detectors.
6. What is isoelectric focusing in electrophoresis?
Isoelectric focusing (IEF) is an electrophoresis technique that separates proteins based on their isoelectric point (pI), the pH at which the net charge is zero.
- A pH gradient is established in the gel.
- Proteins migrate until they reach the pH equal to their pI.
- At pI, the protein stops moving because it has no net charge.
7. What is paper electrophoresis?
Paper electrophoresis is a simple electrophoresis method that separates charged substances using filter paper as the supporting medium.
- The paper is soaked in buffer solution.
- Sample is applied as a small spot on the paper.
- When voltage is applied, ions migrate toward opposite electrodes depending on charge.
8. What is immunoelectrophoresis?
Immunoelectrophoresis is a technique that combines electrophoresis and antigen–antibody reactions to identify specific proteins.
- Proteins are first separated by electrophoresis in a gel.
- Antibodies are added in a trough parallel to the separation.
- Antigen–antibody complexes form visible precipitin lines.
9. On what principle does electrophoresis work?
Electrophoresis works on the principle that charged particles migrate toward the electrode of opposite charge in an electric field.
- Cations move toward the cathode (negative electrode).
- Anions move toward the anode (positive electrode).
- The rate of migration depends on charge, size, shape, and medium resistance.
10. What factors affect the rate of electrophoresis?
The rate of electrophoresis depends mainly on the charge, size of the molecule, electric field strength, and properties of the medium.
- Charge: Higher charge increases migration speed.
- Molecular size: Smaller molecules move faster through gels.
- Electric field strength: Higher voltage increases migration rate.
- Buffer pH and ionic strength: Affect ionization and mobility.
- Gel concentration: Higher concentration slows movement.
