# science project \[particles in a solvent\]

**URL:** <https://boards.straightdope.com/t/science-project-particles-in-a-solvent/608377>\
**Category:** Factual Questions\
**Created:** [January 4, 2012, 2:02pm UTC](https://boards.straightdope.com/t/science-project-particles-in-a-solvent/608377 "2012-01-04T14:02:45Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\
**Post date:** [January 5, 2012, 7:04pm UTC](https://boards.straightdope.com/t/science-project-particles-in-a-solvent/608377/21 "2012-01-05T19:04:19Z")

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> [@scr4](#):
>
> But some of the vanillin would evaporate too, wouldn’t it?

I’m not an expert in this, but I don’t think it would be very much. Isopropyl alcohol is quite [volatile](http://en.wikipedia.org/wiki/Volatility_(chemistry)) at room temperature, having a boiling point of about 83°C. Pure solid vanillin, meanwhile, would be just about to melt at that temperature, and wouldn’t actually boil until 285°C. There’s more to evaporation rates than the relative boiling points of substances, of course, but my guess would be that these are widely enough separated to make a room-temperature evaporation work pretty well. (I await correction from any real chemists who might happen by, though.)

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**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\
**Post date:** [January 5, 2012, 8:06pm UTC](https://boards.straightdope.com/t/science-project-particles-in-a-solvent/608377/22 "2012-01-05T20:06:47Z")

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I’m spending too much time thinking about this, but I found this “ghetto” flash [chromatography](https://www.dmt-nexus.me/forum/default.aspx?g=posts&t=17353)method… it could work. A quantitative analysis would still have to be made to determine the amount of vanillin in the initial solution, but it should be pretty straightforward if you have access to something to measure it with.

A TLC plate could tell you how pure each fraction was.

The combo of flash+TLC chromatography is how I isolated the compounds I was working with in my undergraduate organic chemistry lab. We used a rotary evaporator to remove solvent. In this case, we did the identifications by NMR, but we were looking for a particular isomer.

Man, I can’t wait to have kids and try out kitchen-chemistry 😉

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [January 5, 2012, 10:13pm UTC](https://boards.straightdope.com/t/science-project-particles-in-a-solvent/608377/23 "2012-01-05T22:13:42Z")

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> [@si\_blakely](#):
>
> I’d agree (thus the suggestion to not get too near the saturation limit). You could easily calibrate it with some known concentration samples, though.
> 
> However, for the OP, many years ago in my Analytical Chemistry class, I had to identify an unknown. It was white, crystalline, and had a distinctive sweet odour. I identified it as vanillin before I even got to the IR Spectroscopy bench. It is clear in solution, although I don’t know what the beans/seeds are like in vodka. You may not get good visible results.
> 
> Si

On thinking about it, the answer is simple - use the camera to measure the colour of all of the samples simultaneously (use an eyedropper tool in a photo editing program to sample the colour of a few pixels from each one)

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