chemrox
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column packing materials
When a young ug one of my organic professors was talking about chromatography and told us that a lot of different materials could be used for column
packing. He mentioned that Tide soap had been used. Has anyone here ever used anything besides the usual suspects, silica, alumina ? I have some
tarry product to clean up.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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BromicAcid
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Interesting page here from an older source:
http://web.lemoyne.edu/~giunta/tswett.html
It discusses eluding leaf extracts through columns to obtain the different chlorophylls. Here is a relevant excerpt:
| Quote: | From this point of view I have studied more than a hundred substances belonging to different chemical systems and always with essentially the same
result. I will give here a short summary of the substances tested.
Simple substances (S, Si, Zn, Fe, Al, Pb, Sb); oxides (SiO2, MgO, MnO2, PbO, Sb2O3, Fe2O3, Ag2O, HgO, U3O8); hydroxides (B(OH)3, NaOH, Ba(OH)2,
Al(OH)3); inorganic chlorides (Na, K, NH4, Ca, Mg, Al, Fe, Co, Cu, Hg); chlorates (K, Ba); potassium bromide, potassium iodate; nitrates (K, Ca, Ba,
Pb, Ag, Cu, U); phosphates (K, Na, NH4, Fe); sulfides (K, Hg); sulfite (Na); sulfates (K, Ca, Mg, Ba, Zn, Fe, Mn, Cu); carbonates (Na, K, Ca, Mg, Fe);
silicates (K, asbestos); ammonium molybdate, potassium permanganate, potassium ferricyanide and potassium ferrocyanide, oxalic acid, tartaric acid,
citric acid, quinic acid, tannic acid, uric aid, picric acid, phenolphthalein; oxalates (NH4, Mn); acetates (Pb, Cu); amides (urea, asparagines);
higher alcohols and carbohydrates (mannite, dulcite, sucrose, galactose, inulin, dextrin, amylose); proteins (egg, albumin, peptone, hemoglobin);
trioxymethylene, chloral hydrate, hydroquinone, resorcin, pyrogallol, aniline dyes (gentian violet, chrysoidin, etc.); finally a series of chemically
undefined substances (bone meal and blood meal, soil, kieselguhr).
Some of these substances can also carry down carotin from its petroleum ether solution (HgCl2, CaCl2, PbS, etc.). Many bodies decompose the pigments
adsorbed on them. Some, for example (MnO2, KMnO4, U3O8), destroy the chlorophyll completely, obviously by oxidation. Others act on the chlorophyllines
in the well-known manner of acids; these include the acids mentioned, acid salts, and many neutral salts whose water solutions can acquire an acid
reaction by hydrolysis. |
More than one way to skin the cat for sure. I always wanted to do a study on the use of powdered sugar since it's cheap, the right texture, readily
available, and easily disposed of.
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unionised
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I believe that corn starch has been used (for essentially the reasons Bromic Acid gives for suggesting sugar) but I haven't' tried it. It has the
advantage of being insoluble in most solvents.
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DraconicAcid
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I've heard of chalk and cellulose being used as chromatographic materials. The Tide detergent you mention is also something I've heard before, but
that was in a "dime-store gas chromatography" demonstration. Natural gas as the carrier, detergent as the column material, and a flame with a copper
wire as a detector. It was used for separation of dichloromethane from carbon tetrachloride- when they come out of the column, the flame turns green.
*Note: The above is from memory. I'll try to find a cite later.*
ETA: Found one: http://www.pathfinderscience.net/teachers/flask/act/pdf/chap...
[Edited on 7-2-2013 by DraconicAcid]
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Dr.Bob
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Lots of stuff can be used for some simple things. But if you want to get real separations of somewhat non-polar materials, then silica or alumina is
best. Most of the cheaper ones are very polar, like cellulose, chalk, inorganics, and will mostly bind due to charge or not. Ion exchange resins
work the same. So if you have polar compounds to separate, like neutral from acid from base, then that might work well, but then so would simple
aqueous/organic partitioning, like an acid/base extraction from organic solvents. But if you are trying to separate somewhat similar compounds like
acetophenone from 4-methoxyacetophenone, then something like silica will do best.
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chemrox
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[Edited on 17-2-2013 by chemrox]
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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chemrox
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I'm afraid that Tide might be too coarse for the dry column technique I wanted to use. I do think a sugar might work. Possibly lactose as it is
usually finer than sucrose. Mannitol might be another option. Confectioner's sugar might be fine enough too. I don't have any fine mesh sieves so
have to estimate grain size with a dissecting scope. Maybe grain size and mesh could be derived from porosity.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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