column chromatography using space sand

[deleted-390113]

I live in India and here space sand is unavailable , will the experiment work if I make DIY space sand.

Space Sand is just normal sand that has been exposed to the vapours of a silicon compound called trimethylhyroxysilane. This process changes the composition of the surface of the sand and makes it unable to bond with water.

So if we spray water repellent sprays used for car paints will this work?

[donnahardy2]

Hi,

This is a great project and your question is very perceptive and I think your idea will work well.

https://www.sciencebuddies.org/science- ... p045.shtml

Water repellent sprays are general made from silicone materials similar to the coating used for space sand, so this should work well for the application. Of course, you will need to do the experiment to confirm this. But this should make a great science project.

Here is another option, if you can find it. C18 silica is a hydrophobic column packing material that has been used for this application also.

https://www.flinnsci.com/media/1095893/91806.pdf

Please let us know if you have any other questions.

Donna Hardy

[deleted-390113]

The other problem that I'm facing is the availability of grape soda .In my country grape soda is unavailable however orange soda by popular brand fanta is available .
Is it possible to separate orange soda with the same conditions
Can we separate coloured components from any dye, vegetable leaf or food colour.
What is the criteria for deciding the compound to be separated into its components.
Thank you for helping me !

[donnahardy2]

Hi,

You have an excellent question, and to answer, I need to explain the chemistry of this separation.

Grape soda contains red dye 40 and blue dye 1. Here is the structure of red dye 40, You will notice that red dye 40 contains 3 carbon and hydrogen ring structures which make it hydrophobic and two sulfonic acid groups, which give the molecule a negative charge and also make it polar. The polar character of the molecule allows it to dissolve in water.

https://en.wikipedia.org/wiki/Allura_Red_AC

Blue dye number 1 has more carbon/hydrogen ring structures, so is more hydrophobic compared to red dye 40 and it contains 3 sulfonic acid groups as well as two nitrogen atoms.

https://en.wikipedia.org/wiki/Brilliant_Blue_FCF

The water repellent coating on the space sand is composed of carbon and hydrogen atoms, so is hydrophobic. The sand itself is composed of silicates, which are negatively charged.

Water repellents are composed of molecules like isobutyltrimethoxysilane, which is a silicon atom bonded to multiple methyl (CH3) groups. The silicon interacts with the same groups on the sand and the carbon and hydrogen methyl groups make the surface hydrophobic (or water repellent).

http://www.chemspider.com/Chemical-Structure.79049.html

Molecules that are hydrophobic will interact with other molecules that are hydrophobic. So the two dyes in grape soda bind to the space sand by hydrophobic interaction. The red dye is also slightly repelled by the sand because of the negative charges on the dye and the sand. The blue dye has more carbon/hydrogen rings so is more hydrophobic and it contains 3 sulfonic acid groups, which would repel the sand, and two nitrogen atoms, which would increase the affinity of the molecule for the sand.

The dyes are eluted from the space sand with isopropanol, which is a polar molecule. The isopropanol displaces the dyes one at a time because the blue dye is more hydrophobic compared to the red dye.

Now, I can answer your question. Yellow dye 6 has 3 carbon/hydrogen rings and two sulfonic acid groups, so closely matches the structure of red dye 40, so it is going to be difficult to separate these two dyes using the protocol. It would be better if you could find something with blue dye 1 in it, or find a product with two other dyes. We could check the structure and look for something with a different number of carbon/hydrogen rings and sulfonic acid groups compared to red dye 40.

Is grape kool-aid available? Can you obtain packages of individual food dyes? Please let me know what brightly colored drinks you can obtain locally and what the name of the dyes in the product are. I’m sure there’s something available that would be suitable to use.

Now that I’ve explained the chemistry, perhaps you could search for the chemical structures and let me know what you think would work. If my explanation is not clear, however, let me know and I’ll try again. Let me know if you have had chemistry yet if you need more help with the molecular structures.

Donna