I did TLC for Aspirin and I have two questions I need to answer:
1. the aspirin spot has a shape of a tear (tlc picture added. aspirin marked as A). why?
2. why is the alumina plate green under UV?
thank you!!
Hello Madam,
Did you tried with different mobile phases. If you check the bottom spot of C, it also have some what same shape. Most probably you have to select a different mobile phase.
https://www.researchgate.net/post/What_is_a_solvent_system_for_TLC_of_Aspirin.
This weblink might help you.
Just make sure that you were not using a very old TLC plates.
Hello
1. I think it's an effect of the sample concentration, when it is a large quantity of sample, it saturates the stationary phase and can flow with the solvent front, even when it is supposed to get retained,. But while moving its concentration diminishes, because there is more and more stationary phase where it is retained. Just compare it with the same spot in the mix beside, where the concentration must be lower.
2. Silica gel and alumina used in TLC are supported on aluminum foils, PET or glass plates and have an inorganic fluorescent indicator at 254 nm. Commonly used are Zinc Cadmiun sulfide or Mn-activated zinc silicate.
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