The solvents used for Thin Layer Chromatography (TLC) vary depending on the polarity of the compounds being separated.
In normal-phase TLC, where the stationary phase is polar (like silica gel), the mobile phase (solvent) is typically a mixture of less polar solvents. According to the provided reference, commonly used solvent mixtures include:
- Ethyl Acetate/Hexanes (EtOAc/Hex): This combination is effective for separating less-polar compounds.
- Methanol/Dichloromethane (MeOH/DCM): This mixture is generally used for separating more polar compounds.
The specific ratios of these solvent mixtures can be adjusted to achieve optimal separation. Different solvent mixtures and their varied ratios play a key role in achieving improved separation.
Here's a breakdown of solvent choice in a table for easier understanding:
| Compound Polarity | Common Solvent Mixture |
|---|---|
| Less Polar | Ethyl Acetate/Hexanes (EtOAc/Hex) |
| More Polar | Methanol/Dichloromethane (MeOH/DCM) |
Practical Insight: The choice and ratio of solvents are not fixed and often require experimentation to find the best conditions for separating a specific mixture of compounds. It is common practice to start with a non-polar solvent and increase the polarity gradually until a good separation of compounds is achieved. A trial and error process is usually followed.
Examples of Other Solvents/Mixtures:
- Mixtures containing ether and petroleum ether
- Various ratios of acetone and hexanes
- Pure solvents like ethyl acetate or chloroform may also be used, although solvent mixtures are more common.
In short, solvent selection in TLC depends on the chemical properties of the analytes being investigated, and the solvents listed above are frequently utilized in different ratios to achieve the best results.
