How can you tell which mobile phase is more polar in TLC? (hexane/ethyl acetate/ethanol vs. isopropanol/ammonia)? the hexane/ethyl acetate/ethanol travelled up the TLC faster, does this make it more polar?
The TLC is silica gel!
answered twice below.
To determine which mobile phase is more polar in TLC (thin-layer chromatography), you can look at the movement of the compounds on the TLC plate. The mobile phase that allows the compounds to travel further up the plate is typically less polar.
In TLC, the stationary phase is the silica gel coated on the TLC plate, and the mobile phase is the solvent mixture that moves up the plate. The polarity of the mobile phase affects how strongly the compounds in the mixture bind to the stationary phase. Compounds with higher polarity will have stronger interactions with the stationary phase, resulting in slower movement up the plate.
In your case, if the hexane/ethyl acetate/ethanol mobile phase traveled up the TLC plate faster compared to the isopropanol/ammonia mobile phase, it suggests that the hexane/ethyl acetate/ethanol mobile phase is less polar. This means that the compounds in your mixture have weaker interactions with the stationary phase in the hexane/ethyl acetate/ethanol mobile phase, allowing them to move more easily up the plate. Conversely, the isopropanol/ammonia mobile phase is more polar, leading to stronger interactions between the compounds and the stationary phase, resulting in slower movement.
So, the statement that the hexane/ethyl acetate/ethanol traveled faster does indicate that it is less polar compared to the isopropanol/ammonia mobile phase in TLC.