Paper Chromatography Experiment lies under the section of Elementary School science experiments. Although the textbook science of chromatography is taught at a higher standard, this simple and interesting experiment offers advanced practical knowledge on this topic.
What is Chromatography? – The Basics
In chemistry, chromatography is a very important and essential laboratory technique. It’s a technique for separating the compounds from a mixture of components by dissolving the mixture in a solvent (mobile phase) and passing the solution through a medium (stationary phase). Different components have different affinities to the stationary phase; hence each component in a mixture moves at different rates along with the selected medium or stationary phase, causing them to get separated from each other. This is the basic principle of compound separation using the chromatography technique.
A related article you may find interesting: What is Tree Man Syndrome?
Types of Chromatography
Different types of chromatographic techniques are used to separate different types of mixtures and can be fundamentally divided based on bed shape, bed type, mobile phase, affinity, separation mechanism, etc. Considering all categories, there are 25+ types of chromatographs are used in chemistry for different perspectives.
The following is a list of the most common chromatographic techniques that are used most frequently.
- Column chromatography
- Thin-layer chromatography (TLC)
- Paper chromatography
- Gas chromatography
- Ion exchange chromatography
- Chiral chromatography
- High-performance liquid chromatography
Related Article: Interesting Chemistry Facts
Importance of Chromatography
Chromatography is an essential weapon of chemists, most frequently used in natural product, synthetic, and medicinal chemistry. For instance, the preparations of most medicines initiate from organic chemistry laboratories, the origin may be the plant/animal body extracts or hoods of synthetic laboratories.
A plant/animal body extract contains thousands of isolable compounds, maybe hundreds of those show high bioactive characteristics against specific diseases, while only 1-2 finally convert to marketed drugs. Generally, natural product chemists perform step-wise treatment of the initial extract in several solvents in search of a pure compound. However in general, pure compounds don’t appear after this process, rather they get a mixture limited number of compounds. They have to proceed with further purification for getting pure compounds.
A similar thing happens in the case of laboratory synthesis. After designing a target molecule, chemists create a multi-step reaction scheme to derive the compound. Most of the chemical reactions don’t provide a single product, rather appear to be a mixture of products; this may be a stoichiometric amount of unwanted products or minute impurities. Whatever these are, chemists need to get a pure product in every step to proceed to the next step. And, of course, a similar purification process needs for achieving the final target compound.
Both natural product and synthetic chemists perform chromatography to isolate pure target compounds from the mixture of products. This is the process to derive most medicinal compounds over the world. So, you can understand the potential of chromatography techniques.
Explanation with Example
Suppose, a scientist conducts an organic reaction between A and B. Upon completion of the reaction, it is expected to produce product C; but after structural analysis of the crude, the scientist finds product C is not appearing in pure form, rather it a mixture of two other products that appeared there (suppose D and E).
Now, what the scientist does? He/she goes for separating the mixture to fetch the pure product C, and also to identify the other impurities D and E. This separation can be done using chromatography techniques.
Generally, thin layer chromatography (TLC) and column chromatography techniques are followed to separate organic compounds.
Years back, when chromatographic methods were not established, scientists had to follow lengthy experimental processes to isolate pure compounds. After the invention of this technique, chemistry becomes much faster. If you compare the medicine discovery rate by decades, you’ll find a remarkable growth in medicine discovery after 1960s, and chromatography is majorly responsible for that.
Related Article: Amazing Biology Facts You Must Know About
Can you perform chromatography experiments at home?
At home, it is not possible to perform all types of chromatography experiments because in most cases specific ingredients and equipment are required.
For instance, thin-layer chromatography (TLC) and column chromatography need silica/ alumina plate/ silica/ alumina/ other beds that you can’t access at home. Most of the time-specific organic solvents are used as eluents and UV chamber/UV torch are essential to separate compounds. Although UV torches are available in the market, you can’t have the permit to buy organic solvents for home use.
Most of the other chromatographs need specific machines which as highly expensive and available for laboratory use only.
However, you can try the paper chromatography experiment at home; it doesn’t need any such typical ingredients and equipment.
Related article: Amazing Chemistry Facts
Paper Chromatography experiment: Try it at home
(For middle & high school students)
First, arrange the following Equipment & Ingredients for this experiment:
- 5 Non-permanent markers/ Color candies (Skittles or M&M)
- Table salt
- White Coffee filter
- Plate or foil
- Pitcher/ empty 2-liter bottle/ Tall glass beaker
- Tall glass
- Stick and glue
- Small vials/ clean color palet
- Measuring cups/spoons
Related Aricle you may find interesting: World’s Only Immortal: Facts about Immortal Jellyfish
|1||Cut coffee filter paper measuring a dimension of 8×8 cm. attach a 10 cm stick at one edge of the paper (using glue).|
|2||Use the pencil to draw a 1 cm dotted line from 0.5 cm above the edge of the square filter paper. Don’t use pen.|
|3||Put 6 dots using the pencil along this line; each dot should be 0.5 cm away from the next dot.|
|4||Mark under each dot; such as R for red color, B for blue color, and so on.|
|5||Take 5 vials or the color palette, and add 1 drop of water in each vial/ each box of the color palette.|
|6||Put different colors of marker ink/ candy in different vials/portions of water in the palette. The water portions will get colored; if you are using candy, remove it after the water becomes colored.|
|7||Dip a toothpick into a color and dab the color on the dot that is labeled for that specific color. Repeat the process thrice; keep the color dots as small as possible but should be intense. Use a new toothpick for each color. On the left-most point, put all 5 colors’ dots; this means this point will contain the mixture of all colors.|
|8||After making all 5 color dots, let the filter paper dry. Then repeat the process twice more to make the dots intense.|
|9||After the final touch let the filter paper dry.|
|10||Take 2 cups of water in the 2-liter bottle; add 6 teaspoons of salt and mix well.|
|11||Pour the saltwater in the glass/beaker up to the height of 0.5 cm.|
|12||Place the filter paper in the beaker that contains a salt solution. The solution level should be just below the color dots. You have a stick attached at the top of the filter paper; this will help you to adjust the level.|
|1||The salt solution starts to move upwards along the filter paper.|
|2||You can see the colors are also moving upwards leaving the dots; keep them moving until the saltwater reach the upper edge of the filter paper.|
|3||Remove the filter paper from the beaker when the saltwater reaches close to the upper edge and place it on a plate surface to dry.|
|4||When fully dried, see the result of your chromatography experiment.|
Related article: Spider Tailed Horned Viper: Horrible or Not?
Firstly you can see, all the colors didn’t move equally. Some go close to the top edge, some are close to the bottom edge. You can also observe some inks/candies contain multiple dyes; that means, from the base the colors of the candies break into multiple colors. These inks/candies contain more than one band of colors. The second thing you can observe, some colors moved horizontally at the same rate. This happened because some colors contain the same dyes moved equally along the filter paper.
So, try this paper chromatography experiment at home and understand the science behind chromatography. Also, share the experimental idea to your friends and spread the scientific knowledge.
If you are willing to study with chemistry in future, this knowledge and hands on experiment will keep you a bit ahead. However, in the upcoming issue we are coming with more chemistry experiment idea for you. Just keep following. And yes, if you have any further query about this, don’t hesitate to post you question in the comment box below. I’ll glad to assist you further.