Kitchen Chromatography

Yesterday I did the experiment with the blue inks and I promised I'll talk a bit more about it.This is a cool experiment you can try out yourself in the kitchen. It's easy and you can start to learn some stuff. Even better if you can involve your kids and start to get them interested in science!Chromatography is the process of breaking down something into its parts. It is a Chromato Graph. Not a photo graph. It is a picture of colors. This is going back to the roots of the process -- it typically separated things into different bands of colors.Basically what's going on is you have a solvent (the eluent), water in my example, that will travel through some substrate, in this case the coffee filter, carrying the sample (the analyte) of ink.In my example I'm doing a low-rent version of paper chromatography.The setup is I have strips of some porous paper that are suspended over some water. I make lines of each test ink on each piece of paper. When I'm ready, I dip the bottom of each strip of paper into the water.What's going on behind the scenes in this example is that after I dip the paper into the water, the water starts to move up the paper using capillary action -- the surface tension of the water drags it upward.As the water moves up the strip of paper it eventually gets to the line of ink. When it gets there it dissolves some of the soluble part of the ink and that starts going for the ride.Here's where it gets interesting.Different components of the ink have different molecular weights and varying amounts of polarity. These affect how mobile they are.In the case of sample #1, not a whole lot is dissolvable. This makes sense because this is supposed to be a permanent (on paper) ink. #5 and #6 are interesting ones though.#5, which started out at turquoise, has a base of fixed blue, some relatively mobile light blue that bonds with the paper as it moves, a yellow and an even more mobile deep blue!#6 has a deep blue fixed chunk, some darker blue and a bit of mobile pink.The second gang of tests are even cooler!I'll let you walk through that yourself. Fun stuff!  :-D[smugmug url="http://photos.vec.com/hack/feed.mg?Type=gallery&Data=21079734_47gwB5&format=rss200" imagecount="100" start="1" num="100" thumbsize="Th" link="smugmug-lightbox" captions="false" sort="false" window="true" smugmug="true" size="L"]