Factors to Consider:
* Nature of the compounds:
* Polar compounds: Water, methanol, ethanol, or mixtures of these solvents are often good choices.
* Non-polar compounds: Diethyl ether, hexane, or toluene might be more effective.
* Intermediate polarity: A mixture of polar and non-polar solvents is often used (e.g., a mixture of ethanol and dichloromethane).
* Desired separation:
* Highly similar compounds: You'll need a solvent system with a high resolving power. This usually means a more polar solvent or a solvent mixture that allows fine tuning.
* Very different compounds: A less polar solvent might be sufficient.
Common Solvent Systems:
* Water: Good for separating polar compounds, especially if they are ionic.
* Methanol: A versatile solvent, often used in mixtures to fine-tune polarity.
* Ethanol: Similar to methanol, but less polar.
* Dichloromethane: A good choice for separating non-polar compounds, but can be volatile.
* Hexane: A very non-polar solvent, often used for separating lipids.
Tips for Choosing:
* Start with a known system: If you're unsure, try a solvent system known to work well for the type of compounds you're separating.
* Test different solvent systems: Experimentation is key! Try different mixtures and concentrations of solvents to find the optimal combination for your specific separation.
* Consider safety: Many organic solvents are flammable and/or toxic. Always use proper safety precautions.
Example:
Let's say you're trying to separate different colored inks on a piece of paper. You could start with a simple mixture of water and ethanol. If this doesn't provide good separation, you might try increasing the ethanol concentration or adding a small amount of dichloromethane to the mixture.
Remember: Choosing the right solvent is crucial for successful paper chromatography. Always consider the nature of your compounds and the desired separation when making your choice.
