Hi thank you so much for the videos, I just have one question. When calculating the Rf value and you measure the distance travelled by the component , do you measure up to where the spot starts or when the spot ends (the bottom the the spot or the top)? I don't know if it makes sense...😩
Thank you very much for the videos !!! I just had one question, are these videos for OCR A as well as I didn't know about the % of component or the calibration curve.
1:56 (TLC): I have never understood why the compound that has the weakest adsorption is the one at the top and why the best adsorbent is at the bottom. And what does it imply about the polarity of the compound? Could you help me please? Thanks!
Inigo Bergua The stronger the level of adsorption the more the component ‘grips’ to the stationary phase and hence is moved less by the mobile phase. The polarity question is more relevant to a liquid stationary phase (at A level anyway) and that’s found in gas chromatography. So if you have a polar substance being used for a liquid stationary phase then a polar component will interact more and spend more time in the stat phase and less in the carrier gas so retention time will be longer. If component is non-polar the opposite it the case and a shorter retention time. Situation reversed if a non-polar liquid stationary phase is used. Hope that makes sense. I do that other videos on chromatography btw. 😊
