Thank you prof. Which solvent must use to dissolve silica gel? Is it the same mobile phase, always or can i use hexane only every time to dissolve silica gel? Thank you
How do I know what size of column should be used for a particular compound separation? I mean like, 19 neck column, 24 neck, 36 neck something like that. There are very bigger columns as well. How to know when to use which size of column for separation?
Happy new year and Thank you so much for this video. Is there standard to use silica gel in column, I mean if my sample a little bit like (0.01 gram), how much of silica gel use here? in contrast, if I have a lot of samples such as (1 gram or more), here, how much of silica gel have to use? I mean is there ratio from silica gel to sample to use in column, please tell me
Thank you prof. If I have 0.09 gm of sample or below this .how amount of silica gel need? Also, if I have big amount of compound , here how amount if silica gel need to take? I mean is there ratio or standard from silica gel to sample? Thank you
Would be great to have more explanations (in a separate video?). E.g. why it's important that silica gel is not disturbed or doesn't dry. Or why there is a sand at the bottom. Or what are the roles of both (there were 2?) solvents, etc.. But nice video anyway :)
We were talking about that... these videos are really JUST lab skills, not the theory... but that's definitely something we might do in the future. Thank you for watching! We put your comments on THE LIST!
thank you. If I used wet packing of silica gel to column (slurry), here, can I use any solvent for silica gel until reached slurried, or same mobile phase or must use only hexane.
How do you tell when your compound of interest came through? Do you just TLC all of the collection tubes and see which one shows a spot? How do you know when to stop eluting? Do you just keep doing TLC on what come out of the column until you see your compound on TLC?
You know your compound came through when you see any colors on the process. If it doesn't, I suggest you to check the column and your tubes time to time under the UV light so you know in a glance the separation is really works. And ya, I checked the spots by TLC so I knew which one that have compound and which one is not. How do I know when to stop eluting is when I don't see any visible separation for an hour or so. I guess the sample can't be separated anymore at that time. The last thing I done was washing it using ethanol to make sure all the compounds are came through from the column and not missing any of it. That's what I did on my research earlier. Hope this help!
If I have solid sample containing components, can I use any solvent to dissolve it? Or I have to use only the same mobile phase as solvent to dissolved sample? Another case, if must use same mobile phase, but my sample can not dissolve, here, please I need solution to this problem. can I use any solvent? thank you alot in advane
Hello. I want to separate my components from n-hexane extract with mixture of n-hexane and ethyl acetate (17:3) as the mobile phase, but the sample won't come out at all from the column. It's already adsorbed to the silica gel but it won't go down and get stucked. Do you know what caused this or what should I do to solve this? Thank you.
First of all, make sure your compound is not in the fractions you already collected and you missed it (it happens; if the polarity of the mobile phase was correct by TLC, your compound may have already come out). If it's not there, try eluting more solvent, eventually increasing the polarity. If nothing happens and you get desperate, you can go up to neat ethyl acetate, just to recover your product - at this point you would have no separation. If worse comes to worse, you can try eluting with methanol - that should get it out. Hope this helps.
The silica gel won't go dry due to gravity because of the gel's equilibrium. It will only go dry if the solvent from the top evaporates or you apply pressure
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very informative
Thank you prof. Which solvent must use to dissolve silica gel? Is it the same mobile phase, always or can i use hexane only every time to dissolve silica gel? Thank you
the column used is interesting for having a removable bottom end.
could you tell us its 'name' & the make and model of it and who sells them.
How do I know what size of column should be used for a particular compound separation? I mean like, 19 neck column, 24 neck, 36 neck something like that. There are very bigger columns as well. How to know when to use which size of column for separation?
Can you do a video explaining how clean the silica-gel?
Happy new year and Thank you so much for this video. Is there standard to use silica gel in column, I mean if my sample a little bit like (0.01 gram), how much of silica gel use here?
in contrast, if I have a lot of samples such as (1 gram or more), here, how much of silica gel have to use?
I mean is there ratio from silica gel to sample to use in column, please tell me
Thank you prof. If I have 0.09 gm of sample or below this .how amount of silica gel need?
Also, if I have big amount of compound , here how amount if silica gel need to take?
I mean is there ratio or standard from silica gel to sample? Thank you
Would be great to have more explanations (in a separate video?). E.g. why it's important that silica gel is not disturbed or doesn't dry. Or why there is a sand at the bottom. Or what are the roles of both (there were 2?) solvents, etc.. But nice video anyway :)
We were talking about that... these videos are really JUST lab skills, not the theory... but that's definitely something we might do in the future. Thank you for watching! We put your comments on THE LIST!
really helpful
thank you. If I used wet packing of silica gel to column (slurry),
here, can I use any solvent for silica gel until reached slurried, or same mobile phase or must use only hexane.
Very nice and lovely video
Thank you for this video! I have one question: how I can regenerate the silica-gel after using it in the column?
Good question! In theory, yes - if you clean it with methanol. In practice, no one does it because it's never really clean enough to trust.
You can regenerate your silica gel after using it in the column chromatography by thermal heating in an oven at 600degree Celsius for 2hrs.
How do you tell when your compound of interest came through? Do you just TLC all of the collection tubes and see which one shows a spot? How do you know when to stop eluting? Do you just keep doing TLC on what come out of the column until you see your compound on TLC?
You know your compound came through when you see any colors on the process. If it doesn't, I suggest you to check the column and your tubes time to time under the UV light so you know in a glance the separation is really works. And ya, I checked the spots by TLC so I knew which one that have compound and which one is not. How do I know when to stop eluting is when I don't see any visible separation for an hour or so. I guess the sample can't be separated anymore at that time. The last thing I done was washing it using ethanol to make sure all the compounds are came through from the column and not missing any of it. That's what I did on my research earlier. Hope this help!
Which type of sand is used for the column chromatography, is there any specifications sir
If I have solid sample containing components,
can I use any solvent to dissolve it?
Or I have to use only the same mobile phase as solvent to dissolved sample?
Another case, if must use same mobile phase, but my sample can not dissolve, here, please I need solution to this problem. can I use any solvent? thank you alot in advane
What solvent use to dissolve the sample? Is it hexane ethyl acetate??
Hello. I want to separate my components from n-hexane extract with mixture of n-hexane and ethyl acetate (17:3) as the mobile phase, but the sample won't come out at all from the column. It's already adsorbed to the silica gel but it won't go down and get stucked. Do you know what caused this or what should I do to solve this? Thank you.
First of all, make sure your compound is not in the fractions you already collected and you missed it (it happens; if the polarity of the mobile phase was correct by TLC, your compound may have already come out). If it's not there, try eluting more solvent, eventually increasing the polarity. If nothing happens and you get desperate, you can go up to neat ethyl acetate, just to recover your product - at this point you would have no separation. If worse comes to worse, you can try eluting with methanol - that should get it out. Hope this helps.
How many times can the packed column be used? Is it possible to salvage the glass column?
The silica gel won't go dry due to gravity because of the gel's equilibrium. It will only go dry if the solvent from the top evaporates or you apply pressure
Well done.
A good information
Thank you so much 👍👍
Most welcome 😊
hi, is this the same process with packing sephadex LH-20?
Thank you!!!!
You're welcome! Glad it was helpful.
Thank you for not using technical gibberish like 'eluent' so that regular, uneducated people can understand this stuff!! :)
Why we put coton
What kind of sand do you use?
The sandy type of sand
Ottawa sand
hypeeeeeee
What did he say 2:39-2:41? “A mixture of .... and ...”
a mixture of Hexane and Ethyl Acetate
What's TRC?
Camila Cruz Pérez He said TLC or Thin Layer Chromatography ..the caption was wrong lol
TLC
Ma e' italiano?
Pls attached subtitle
Fixed! We re-did them today. Thanks for letting us know.