What are good TLC solvents?
Solvent Systems for Thin Layer Chromatography
- Polar compounds: 100% EtOAc or 5% MeOH/dichloromethane.
- Normal compounds: 10-50% EtOAc/Hexane.
- Nonpolar compounds: 5% EtOAc/hexane, 5% ether/hexane, 100% hexane.
What types of compounds are suitable for TLC?
TLC is a highly versatile separation method that is widely used for both qualitative and quantitative sample analysis. TLC can be used to analyze virtually any substance class, including pesticides, steroids, alkaloids, lipids, nucleotides, glycosides, carbohydrates, and fatty acids.
Does solvent matter in TLC?
The solvent level has to be below the starting line of the TLC, otherwise the spots will dissolve away. Non-polar solvents will force non-polar compounds to the top of the plate, because the compounds dissolve well and do not interact with the polar stationary phase.
How do you choose a solvent for column chromatography?
The solvent system which gives maximum separation of the spots will be better solvent for column chromatography. Usually volatile solvents are better than non-volatile solvents .
Why is acetone used in TLC?
Answer: Acetone is a more polar solvent than is hexanes. Since each compound travels faster, each compound would have a larger Rf value if acetone were used to elute than when hexanes is used to elute the TLC plate.
What is the best solvent for chromatography?
Readily Available Solvents for Paper Chromatography
| Solvent | Polarity (arbitrary scale of 1-5) | Suitability |
|---|---|---|
| Water | 1 – Most polar | Good |
| Rubbing alcohol (ethyl type) or denatured alcohol | 2 – High polarity | Good |
| Rubbing alcohol (isopropyl type) | 3 – Medium polarity | Good |
| Vinegar | 3 – Medium polarity | Good |
Why is silica gel used in TLC?
Silica gel is by far the most widely used adsorbent and remains the dominant stationary phase for TLC. The surface of silica gel with the highest concentration of geminal and associated silanols is favored most for the chromatography of basic compounds because these silanols are less acidic.
Why is ethyl acetate a good solvent for TLC?
Ethyl acetate is a polar aprotic solvent, non-nucleophilic in nature. There is a possibility that your compound might have reacted with metanol. However, if you actually ran your second TLC in metanol, your compound might have moved all the way up with the solvent front because methanol is very polar.
How do you determine the best solvent for TLC?
For instance, in determining the solvent system for a flash chromatography procedure, the ideal system is the one that moves the desired component of the mixture to a TLC Rf of 0.25-0.35 and will separate this component from its nearest neighbor by difference in TLC Rf values of at least 0.20.
Is hexane a good solvent for TLC?
Miscibility is the main reason for using a mixture of of ethyl acetate and hexane as an eluent. most routinely used TLC solvent system in organic chemistry is Hexane: ethyl acetate (miscible in all ratio) and DCM: MeoH.
Why is hexane a bad solvent for TLC?
It’s all about polarity matter. Hexane is a non-polar solvent, hence we usually start column from hexane and increase polarity slowly by using either ethyl acetate or DCM (it depends). Methanol is highly polar.
What is the difference between silica and silica gel?
Silica gel is a form of silica that’s processed into various forms like granules or beads. Silica gel works like a sponge, drawing moisture into its many pores.