Quarantine Chromatography

Science Should Never Halt

As parents and students continue to quarantine, socially distance, wash their hands, and avoid touching their face (you are following all of the coronavirus recommendations, right?), it’s important that inquiry and exploration are still allowed to thrive. Last week we introduced a contest for students, parents, teachers – or anyone excited to explore a little kitchen science – to send us images of their best experiments. We have already seen numerous ways that you are all keeping busy, exploring the natural world, and flexing your mental muscles. Keep it up, scientists!

If you’ve found yourself desperately searching for entertaining and educational activities, we will be releasing a series of Edvotek at Home activities. Our first, a deep dive into the Enzyme-linked Immunosorbent Assay (ELISA) is available now. Stay tuned for more later this week!

For those of you looking for an immediate science fix, today we will be writing about performing chromatography using things you can easily find around the house. This experiment is adaptable to multiple levels, involves a hearty dose of inquiry, and will bring a little color into your kitchen.

Quarantine Chromatography

Let’s start with a little background. Chromatography is a chemical process that separates complex mixtures based on their abilities to dissolve in a solution, adhere to each other, and stick to a solid support. This process is incredibly useful for determining exactly what is in a mixture and for identifying contaminants or ensuring that a compound is pure. In paper chromatography, the samples are applied to a strip of paper which is then placed into a solvent, a liquid capable of dissolving our samples. As the solvent moves up the chromatography paper it will carry some of the samples along with it. Importantly, not all compounds will be equally soluble, so a gradient will form, allowing scientists to separate different substances from that original sample.

It is possible to use chromatography to separate out many different substances around your house. Ink, candy, and food coloring are commonly used, but our chromatography adventure started with a short nature hike. Spring is hitting hard in our part of the world, and leaves, grasses, flowers, and… rocks were collected for analysis back home. Our preschooler was encouraged to explore and find things that he thought were exciting and colorful, but you can expand this easily by identifying the plants you encounter (one of our scientists swears by the Plantnet App). Once our collection was complete we returned home to catalog our haul.

The chromatography experiment used materials we had easily on hand: coffee filters, paper towels, tape, water, and isopropyl alcohol. We started by cutting strips of coffee filter and paper towel, and then smashed the leaves and flowers into the paper using a metal coin. The idea here is to transfer just a small amount of the colored pigment to your filter paper. Try to keep the sample at least 1 cm from the bottom of your strip – this will be the part that we stick into our solvent later.

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Once everything had been smashed and smeared, we taped the strip to the inside of some drinking glasses and added the solvents. For our simple experiment we used either tap water or isopropyl alcohol, but different compounds will require different solvents. This can be another great opportunity to expand the lesson – test the same compounds with different solvents and compare the separation. 

This experiment took approximately 10 minutes for the solvents to travel up the paper strips, and then another 10 minutes to dry. Once completed, we were left with colorful, and informative, chromatography sheets. Our preschooler was excited enough that he even performed a followup experiment using markers from his art supplies and has been begging us to take another nature walk. It’s hard to argue that this was anything but a huge success.

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We want to see your chromatography experiments! Give it a try, let us know how it goes, and enter our ongoing contest on Twitter, Facebook, and Instagram. Good luck!