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I believe I just proved that you can.

It was a mixture of two solvents, I honestly don't remember what they were.

Thank you so much! It amazes me that this video is still helping people all these years later!

Thank you, I'm glad you liked it,! As much as I love sustainability, this is a one-time use material. As this is a purification technique, it's essential that the silica and sand are both very clean, and there is no good way to wash them.

Not really, it's more that the compound has a higher affinity for the eluent than it does for the silica. The silica doesn't absorb anything either, it absorbs (compounds stick to the outside of it instead of going inside).

Thank you so much for your kind compliments, I really love to see how many people are still using this horribly long and boring video to learn! I think your question has a couple of different points to consider, but be forewarned that I know very little about size exclusion chromatography. First, if you change the polarity of rhe solvent, would those change the way in which it interacts with the polymer chains? If it does, could this change the size of the coils? If it does, I think that might change the retention times because they won't permeate the beads in the same way. Second, if you do have a very large polarity change, will this have an effect on the stationary phase itself? If it irreversibly bonds to the stationary phase, will it effectively decrease the pore size? If so, I would think that could also affect retention times. I thinknyour safest bet would be to stick with eluents that have similar polarities but different viscosity. And then you could maybe do a second paper looking at same viscosity but different polarity 😉

They are Uvex Stealth, and very comfortable! Try to find the elastic strap version, the neoprene strap gets brittle and breaks in under a year.

Thank you!

The sand is dry, but if i rinsed any of it down it was thw firat solvent mix that i was going to run through the column (which js what you mix with the silica gel with to pour it into the column too)

Obrigado!

Oof it's been a while. I want to say it's a 1.5cm diameter column. I bought those almost 10 years ago!

@@bethg7026 thanks for information Mrs. Beth

You're welcome, but I think this is the one where my audio was horrible because I had to record it in an airport, so sorry for that!

@@bethg7026 Its all good, it helped me a lot!

Hahaha I was SO nervous...the last column I had run was back when I was taking undergraduate organic chemistry, way back in 2000. And I've not run once since that video either!

@@bethg7026 You killed it! I did the dye mix today but I used Brilliant cresyl blue, Methylene blue and neutral red. I got a very clear red/blue separation but not two blue spots. I used isopropyl alcohol to dilute the dyes, dotted the plate, then placed in the chamber with 1:1 acetone:water. Any idea what eluent I could use for separating the blues?

@@lilibeldelapuente2163 I honestly don't know, but you can try using TLC to play around with the polarity of your solvent mix. Figuring out the solvent mix is all about trying to get one to move faster than the other by making one like the solvent more than the silica.

You're welcome!

I honestly dont remember what my eluent was, but you use whatever eluent mixture you are going to start with.

@@bethg7026 thank u 😊

If its not soluble in your selected mobile phaseyou need to change mobile phases. Your compound has to be soluble or it won't move down the column...

@@bethg7026 thank you

Now that I've not even thought about columns other than to answer these videos, I'm a little vague on the details, but if I remember correctly you typically pack it with the same solvent mixture you intend to run through it first.

@@bethg7026 ok thank you

General rule of thumb is 30g silica for every 1g of sample. When I was making .1g batches of product in graduate school I used a pasteur pipet as my column.

@@bethg7026 ok thank you so much

There was but I don't remember how much I used! Its really a balance between how much product you are running through the column and how effective your eluents are at separating your compounds. A good rule of thumb is 1:30 (30g silica per 1g of compound) for gravity columns.

You are more than welcome 😀

Not when it isn't airborne, which it won't be when it's slurried into a solvent. When our students are ppuring it dry, its in a fume hood. I chose not to film anything inside hoods because of the background noise. Also, silicosis is a hazard upon chronic respiratory exposure, not acute. But, both for the protection of the instructors and for any students who are also being exposed to respirable silica elsewhere in their lives, dry silica is used in our fume hoods. The only time they pour it out of the hoods is when it's being poured as a slurry into the column.

You're welcome, I'm glad it helped!

What information are you looking for?

@@bethg7026 thanks, i would like to know the height and diameter of the chromatographic column

@@tuhoang9569 oh boy, it's been a while since I made this video, and I've not been in that department in over 3 years now. I want to say that was a 1.5cm diameter column, and maybe 18" tall...it was way too tall for what I needed, but I couldn't get one any shorter.

Да, я предпочитаю длинные ногти. То, что «на ее пальцах», - это шины, которые предотвращают раздвоение суставов пальцев из-за моего заболевания соединительной ткани. То, что «загрязняет воронку», - это химические вещества в смеси, которую я разделял. Здесь нет смущения ни в чем, кроме ваших постыдных оскорблений.

Why thank you!

Thank you Nimrah, I'm glad you found it helpful!

A couple words of caution here...first, don't be a home-based drug scientist. Just don't. Second, don't buy chemicals, solvents or materials that are not pharmaceutical-grade and use them on something you intend to ingest/inhale/inject/put on your skin. Third, don't mix your stuff with something toxic unless you are 100% certain that you can get every last trace of that toxic substance out. Simple evaporation is not guaranteed to get rid of 100% of the methanol, as it may bind to the product, form an azeoptrope, etc. Basically...don't go there. Please, for your own safety.

Wow that is an amazing compliment, given how bored watching this entire thing makes me!

Yes, that's where i say that the least polar comes off first...

@@bethg7026 hhhhhhh yes. I have been mixing up between normal and reverse chromatography. I love your video! especially with the way we've been studying this has been the best thing ever..thank you!

@@nassimabk3714 aww what wonderful praise, I'm glad that it helped you!!

I'm glad that you liked this video! I would be more than happy to, can you dm me on twitter (@bethg79)?

No, this will just add more silica, and possibly air bubbles, to the column. You don't have to add the sand but it protects the top of the silica column from being disrupted when you add your eluent, which will mess up how nearly your bands elute.

Thank you so much! I highly recommend those mantles!

Thank you so much Rajesh!

Hi there! In terms of solubility of alumina, you've nothing to worry about, it's not soluble in anything that i know of except concentrated strong base (KOH). It will not dissolve in water or organic solvents Now for the cautions. You can use alumina, but it's not something that you can just swap in and expect the same eluent to work. Alumina is more polar, preferentially binds acidic compounds (silica does this to bases, and in fact most amine separations are done with alumina because they like to bind too strongly to silica), and comes in different pH's (acidic, neutral and basic) and different water content (type I, II or III). It's not as easy as the "this jar of silica will work for pretty much anything", and we don't generally start with it because it can take so much time an wasted product to figure out how to make alumina work. Usually, if you can separate using silica, you go for silica. It's just easier. Alumina is usually used if silica fails, which is often when you have basic compounds, compounds that are not acid-stable (silica is slightly acidic and will destroy those), or your compounds are so similar in structure that you need the enhanced polarity of alumina to get better separation. There are likely lots of internet pages that go into good detail on this, I would suggest looking up "alumina vs silica" to get more details to help you!

Those are actually braces for my finger joints, I have a connective tissue disorder and my joints are able to bend backwards, shift sideways, and dislocate. So when I am doing things like opening a bunch of bottles and using stopcocks I need to wear them

Sure! Ammonium sulfate in the mobile phase interacts with the protein to have it expose more of its hydrophobic areas, which are what stick to the stationary phase.

@@bethg7026 Thank you so much

Thanks, I'm glad you found it helpful!

Oh my goodness, in over 3 years I've never known that I mis-spoke there and said the least polar is the one that moves the most AND its the one that moves the least! Some day I'll pull this back onto my computer, throw in a correction and re-upload it!

Hi! How much silica did you use?

@Pamela Loise Marquez looks like 10mL from the beaker. Sorry, this was so long ago and I don't have the manual any more

I agree, keck clips are terrific. Unfortunately with the number of students we have, too many wind up broken, so we went old school.

@@gregbradshaw8679 So long ask your keck clips aren't cracked, they should work even better than rubber bands. We were too poor to be able to let the students melt them (back then keck clips were almost $10 each, and the one by the heating mantle would often wind up melted), so we used these instead.

Thank you!