Dyes in water-soluble markers can be separated using a technique called chromatography.
Understanding Chromatography
Chromatography is a method to separate a mixture of compounds. It works by passing a solution, which contains the mixture, over a non-moving material. The solution that moves is called the mobile phase, and the non-moving material is known as the stationary phase. Different components of the mixture will interact differently with both phases. This results in the separation of those components as they travel at different rates through the stationary phase.
Applying Chromatography to Water-Soluble Markers
In the context of separating dyes from water-soluble markers, here's how the process works:
Materials Required:
- Water-soluble markers
- Filter paper (or chromatography paper)
- Water
- A container or glass
- A ruler
- A pencil
- Clips or tape
The Process:
- Preparation:
- Cut a strip of filter paper and draw a horizontal line (using a pencil) about 1-2 cm from the bottom.
- Place a small dot of the marker on the pencil line.
- Setup:
- Pour a small amount of water into the container to a level that is below the pencil line.
- Suspend the filter paper strip in the container, ensuring the bottom edge just touches the water, but the marker dot does not get submerged.
- Separation:
- As the water moves up the filter paper (the mobile phase), the dyes in the marker are carried along.
- The filter paper acts as the stationary phase.
- Different dyes in the marker will move at different rates due to their varying interactions with the paper and the water.
- Observation:
- As the water rises up the paper, you will notice the original ink dot separating into the different color components that make it up.
How it works with reference:
The reference mentions, "Chromatography separates mixtures of compounds by passing a solution containing the mixture, called the "mobile phase" over a non-moving material, called the "stationary phase." In this activity, water is the mobile phase and the filter paper is the stationary phase."
This confirms that in this experiment, the water is the mobile phase, carrying the ink along, and the filter paper is the stationary phase, where separation occurs.
Example and Insights
- A black water-soluble marker often separates into multiple colors, such as blues, reds, yellows, etc. This shows that black ink is often a mixture of different colored dyes.
- The distance each dye travels depends on its chemical properties and interactions with the paper and water.
- The separation is influenced by factors such as the type of filter paper used and the type of solvent used for the mobile phase.
Summary
By using chromatography, specifically paper chromatography in this case, the individual dye components within a water-soluble marker can be separated and visualized. This is due to each dye component moving at a different rate across the stationary phase as the mobile phase carries it along.
