TLC vs. Column chromatography

[bxs023100]

---

Members don't see this ad.

question, on which kind do polar molecules elute faster than non-polar. and in the TLC, the greater Rf value goes to what kind of molecule?

 

[Lonely Sol]

question, on which kind do polar molecules elute faster than non-polar. and in the TLC, the greater Rf value goes to what kind of molecule?

1) Well, TLC and column are essentially the same type of separtion technique (liquid-solid separations) where solid is the stationary phase, usually silica and a solvent as the mobile phase. On both of these, the polar compound is eluted last because the more polar the compound, more it will H-bond to the silica gel (which has O- on its side chain) causing it to be retained. However, if you are using a reverse phase chromatography, then polar compounds are eluted first. Reversed phase is done on both TLC and column chromatography.

Also, know that in normal phase, the stationary phase is polar and mobile phase is non-polar (solvent) and vice versa for reverse phase.

2) High Rf value is given to more nonpolar compounds since they are less retained.