What factors influence the Rf value of an organic compound.
(there could be more than one options)
1)Polarity of the solvent.
2)Polarity of the compound.
3)Time and/or temperature during the development of the plate.
4)Molecular weight of the compound.
5)Length of the TLC plate.
anyone has any idea?thank you
2007-06-26 10:31:52 · 5 answers · asked by ichigokun 1 in Science & Mathematics ➔ Chemistry
yea.Thank you for your idea.i am not sure which do influence the Rf value from the options above.Do all of them influence or some of them actually do?Can anyone give me a more sure response please?thank you.=)
2007-06-26 10:53:44 · update #1
The polarity of the solvent and the polarity of the compound are the major factors influencing Rf. Since Rf is a proportion the length of the plate and the time will not cause the Rf to differ. MW weight and temp will also not effect Rf. I hope this helps.
2007-06-26 10:59:04 · answer #1 · answered by Anonymous · 0⤊ 0⤋
1)Polarity of the solvent affects the Rf value
2)Polarity of the compound affects the Rf value
3)Time and/or temperature during the development of the plate.
If you mean how long you allow it to sit in the solvent in the tank then No. How long it take is how long it takes. The temperature will have an effect on how long the experiment takes but not on how far it travels.
4)Molecular weight of the compound has no effect on the Rf.
5)Length of the TLC plate has no affect on the Rf value, however the material that the plate is made of can have an effect.
2007-06-26 12:24:54 · answer #2 · answered by scott k 4 · 0⤊ 0⤋
The answer is 1 and 2.
TLC plates have a layer of soild. usually silica (in org. lab) which is polar. This is the stationary phase. The target solution will be dabbed onto the stationary phase then dipped in a solvent the molbile phase. The mobile phase will move up the plate carring the compounds with it.
Lets say the stationary phase is silica, a polar compound. Polar compounds will prefer to hang out with the silica then move with the mobile phase as it moves up the plate, therefore they will be slower to elute, and remain lower on the plate. So the order they move is dictated by thier polarity.
However, how far they will move is determined by the polarity of the solvent, the mobile phase, that is used. If you have a polar solvent and polar compounds with a polar solvent the compounds will not move. So in this particular case you would want to used a nonpolar solvent to get separation.
in the lab you have to use trial and error to find a proper solvent system. but just to give you an idea.
2007-06-26 12:16:28 · answer #3 · answered by shea 5 · 0⤊ 0⤋
I have a lot of ideas. Some are related to the problem above.
Chromatography works to some degree based upon polarity of solvent (carrier) and compound because this determines the affinity of the compound for the solvent and its ability to migrate.
Temperature affects solubility of compound in solvent which affects the solvent's ability to migrate the compound.
Time is not so critical as long as you have had enough time to separate
MW may have an influence but it is minor
TLC Plate length - has to be long enough to get separation
2007-06-26 10:38:36 · answer #4 · answered by GTB 7 · 0⤊ 0⤋
Thin layer chromatography(TLC) is a technique to find the dyes in a specimen.It is used in forensics to identify a certain piece of clothing be cause paint or dyes differ in chemical composition, even the ones that are supposed to be completely similar. This usually does narrow the range to a much smaller amount.
2016-04-01 06:02:51 · answer #5 · answered by ? 4 · 0⤊ 0⤋