Frapto 25 – Glowbug Dude
When my sister last visited home, she cleared out a lot of her crap from the loft. She wanted to take this glowbug dude back with her, but somehow it ended up on my window ledge. At night it eerily glows in the dark.
Now playing: Frightened Rabbit – Be Less Rude
via FoxyTunes
‘Twas the night before Thanksgiving…
Column Chromatography
It’s fitting that I’m blogging about work since that’s what I’ve been doing this week while you Yanks were feasting…
Chemical reactions, especially in organic chemistry, don’t always go cleanly from A + B —> C. Often, you get a bunch of side products (“crap”) that has to be separated from the target product you want. Chromatography helps you with that.
In a column chromatography (one of many types), silica gel (SiO2 + a mixture of solvents) is poured into a long glass tube (right). In a mixture of different chemicals, each one typically has a slightly different affinity for silica due to differences in polarity. When you load your mixture of chemicals on this gel and supply it with a continual stream of organic solvents, you can separate each component based on this affinity difference. Basically, if a chemical species binds tightly to silica molecules, it would take longer to flush it out than chemicals that only binds to silica lightly.
A series of test tubes are used to collect each “fraction” of the column in order of elution. If one has done it correctly, each tube should only have one chemical species in it. By simply evaporating the volatile solvent, a clean, pure sample of what you want can be retrieved. Of course, the actual process of columning is much more involved and involves a lot of complications, but I don’t think I need to discuss those here!
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