Thin layer chromatography (TLC) | Chemical processes | MCAT | Khan Academy

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Learn about how chemicals can be separated based on polarity through thin layer chromatography (TLC). By Angela Guerrero. . Created by Angela Guerrero.
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16 сен 2013

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Комментарии : 132

@novacrystalas 10 лет назад

You explained TLC better than my university chemistry professor in half the time.

@panagiotisatmatzidis9972 9 лет назад

I wonder if that's because in the class we don't pay any attention, while in the exam session our dopamin/serotonin receptors suddenly get busy... Or some people are just charismatic while others, simply are not.

@novacrystalas 9 лет назад

Panagiotis Atmatzidis No, I really do believe her explanation was simply great. My chemistry class had severely curved grading because everyone basically failed. I suspect that everyone did poorly because the professor was not good at lecturing. The professor was a wonderful and likeable person, but his lectures were bad. For example I got something like 50% on the final and received an A- in the course because the grading was adjusted so much. Everyone in that class had horrible grades. My test marks were usually 30-40% higher than the class average, but I still felt like nothing made sense in his class... I really did try hard and pay attention too.

@mohdmursal4104 4 года назад

I agree

@ernakristiana365 4 года назад

@@panagiotisatmatzidis9972 haha true😆

@joanneb2454 4 года назад

@@novacrystalas is this professor from LA lol?

@c.leonoranymo2232 8 лет назад

oh boy, did you just save my ass

@deltaloraine 4 года назад

THANK YOU! I have my organic chemistry lab this afternoon and the lab manual did not explain clearly what the TLC experiment was going to look like. I feel more confident now haha

@noshintarannum9152 9 лет назад

Thank you so much! i have all my confusions cleared out!

@mirlandewilson8267 5 лет назад

A very simple explanation and to the point. Thank you!

@saff1257 4 года назад

stationary phase: the plate with silica gel on it mobile phase: the solvent or mixture of solvents in a beaker draw a pencil line 10mm up on the plate. use a toothpick to dot the sample onto the plate put 9mm2 of the solvent in a beaker. place plate in beaker. add a lid. wait for the mobile phase to move, until it’s almost at the top. take it out and draw a pencil line where it got up to. use a uv lamp to see the results. parts that moved further were more attracted to the solvent- less polar. parts that moved less far were more attracted to the silica (which is very polar) - so they are more polar

@adityaiyengar152 8 лет назад

Awesome explanation! Thanks!

@MrLolza69 10 лет назад

Thanks for the help! Good for high school as well :P

@dishnihareen3703 3 года назад

thank you. this helped me a lot to get through my lessons. nice work, well done

@rabiya5229 8 лет назад

Clear and concise explanation. Thank you!

@moseshayab8497 5 лет назад

This piece was really simple and understandable. Thanks a lot. more insight to you, dear.

@saff1257 4 года назад

moved far: less polar attracted more to solvent moved not far: more polar attracted more to silica gel silica gel is very polar

@joanneb2454 4 года назад

I think this is wrong explaination! moved far: less polar, less attracted to the solvent moved not far: more polar, more attracted to the solvent solvent is polar.

@jobis34 4 года назад

yehudit wolfe No silica gel is polar. She even said that in the video. So they will use a non-polar mobile phase. They CAN switch those two.. but in this video that was the case

@antonymp1992 4 года назад

@@jobis34 👍

@MrMusicLyrics12 10 лет назад

Thank you! I am doing this for school :P ty :D

@ahmedramzy8327 8 лет назад

this was just perfect 😍

@salehalhalabi4127 5 лет назад

Thank you so much you helped me a lot ❤

@gullofficial 4 месяца назад

You saved my time and made this concept crystal clear to me.. Thank you very much ☺☺✨

@thalesm4056 7 лет назад

I loved this explanation. thanks

@shankysingam 9 лет назад

Brilliant explanation. Very useful

@angeecelinova7760 2 года назад

The way my profesor explained was in such way I didn't understand at all. Your graphic really helped me, thank you

@ChemicalEngineeringGuy 8 лет назад

beautiful and effective explanation =)

@rembeck8549 6 лет назад

Thank you!

@EndermanBoss 6 лет назад

Thanks

@cek3800 7 лет назад

Well explained!!!!

@oydeekoi8271 8 лет назад

Thank you so much! :)

@idarmistorres3156 9 лет назад

great!!

@nuni2136 10 лет назад

thanks.

@foolstudent8669 10 лет назад

nice video! thank you :)

@MaideCanyakar 5 лет назад

Thank you

@bapkim-ib9uj Год назад

thank you !

@INCGJEntertainment 10 лет назад

thanks !!

@totalfootball4452 3 года назад

very well explained . Thanks

@alinahussain92 5 лет назад

Helpful...

@Keyvan100 10 лет назад

fire.

@ilhanthediamondcrafter9767 2 года назад

Thank you for the knowledge

@fejiroedeki9014 3 года назад

Thank youuu

@abramgrey2237 5 лет назад

You saved me!!❤

@yoony8856 4 года назад

thank u sooooo much !!!

@directionerforever1238 Год назад

THANKS SM

@rasha341 7 лет назад

thank you 😃

@Angelub 7 лет назад

THANK YOU! I hate reading my MCAT books, this helps

@A_copywriter 3 года назад

Thank you very much💕

@ellien4191 10 лет назад

Thank you! And can I ask what programme you use to record your voice and what you're doing? Thanks!!

@lixx1414 7 лет назад

GRACIAS

@jddasadia 9 лет назад

thnks i got my all fundas clear...........

@sehajpreetkaur4604 4 года назад

Amazing video❤

@bhaveshverma1906 6 лет назад

very good video for study tlc chromatography

@titi14fan 9 лет назад

thank u

@rajaroychoudhuri7451 3 года назад

Thanks khan academy for such alucid exploration

@alhaeri1 4 года назад

thank you

@Eren-gc9ne 5 лет назад

You are amazing

@WorldRandom3D 10 лет назад

Perfect for F324

@anikaterajiv7381 3 года назад

What an amazing voice

@laarayb97 10 лет назад

Im doing this in yr 12 chemistry and I was so confused, but this vedio absoloutly cleared TLC for me, perfect :D

@nadamouradelzayat7833 6 лет назад

Please, I want the method of separation mixture of soluble acid and soluble phenols

@josh.c36 6 лет назад

Could you do one on paper chromatography with a polar solvent?

@AdityaSharma-tc5fp 8 лет назад

we can even use ninhydrine for visualization of spots

@Spoooky738 6 лет назад

Aditya Sharma only for aminoacids

@kennyyong7694 3 года назад

Excuse me, do you know how to prepare silica gel to absorb moisture or silica gel to act as the stationary phase in thin layer chromatography. I need to prepare TLC plate by my own.

@Un1ted-Kingdom 10 лет назад

Good :)

@relaxingsounds91553 3 года назад

You are a life saver ❤

@lawson9738 Год назад

Your Welcome 😁

@diya9707 6 лет назад

Oh god, I have an o chem test tomorrow, and this helped me so much..thankyou!

@comoplaysdestiny5106 3 года назад

how did the test go?

@akhil1802 3 года назад

@@comoplaysdestiny5106 lmao 2 years ago. I'm pretty sure she/he would've forgotten

@quinxx12 3 года назад

Your voice to me is what the silica gel is to the polar compound :DD

@bettinahurlimann3420 7 лет назад

Thank u so much!! U literally saved my ass!

@Leen-ih8ql 3 года назад

what are the methods or ways of separating plant pigments?? only TLC and paper chromatography ?? please I need help

@sanjaycsalunkhe5381 6 лет назад

with this i can get passed for 3rd level homi bhaba 6th grade

@leeman4394 2 года назад

Hell ya baby i love TLC, especially the my 600lbs wife videos and sister wives

@mariammansour291 7 лет назад

What if you use a polar solvent? Would that change the distance the spots travel? Wouldn't the nonpolar compound not travel as much because of the polar solvent?

@jordanjuan9 7 лет назад

it would be opposite effect

@shaweeeeng5963 5 лет назад

What's little spot there in stationary phase?

@kakeungchu2173 8 лет назад

an cutie tone

@SteveAustin00 5 лет назад

Wow

@reubenfernandes9917 5 лет назад

*An cute tone

@afroditi5760 4 года назад

@@reubenfernandes9917 a*

@philipmcniel4908 6 лет назад

I realized in lab this morning that if you used letter-writing paper for TLC, you would literally have a "stationery phase"

@doda-os3bp 2 года назад

why is it called separation method isnt it just straight up detection

@aadityatiwari5676 7 лет назад

isnt silica overall nonpolar tho...if its the stationary phase why did she call it very polar?

@nabilaaulia9361 5 лет назад

And now I know, finally.............. :")

@deephealthcare 7 лет назад

hindi me bhi kuj lessons banaye aap

@brutalpsychedic 4 года назад

2020 and they are still hot

@tgrmln93 10 лет назад

God, ur lovely voice.... make me wanna.... thanks for ur great explanations :)

@imosdefinite 2 года назад

what's a spotter?

@imosdefinite 2 года назад

0:50

@mercedesmalone973 9 лет назад

what is the Rf ????

@andreistephen4965 9 лет назад

the Rf vale is the distance moved by the component or part of the original substance/ the solvent front the point the solvent moved up to. =)

@mercedesmalone973 9 лет назад

so sad that most chemistry books dont cover this. how does rf value relate to polarity?

@andreistephen4965 9 лет назад

Mercedes Malone I have not gotten to that yet on my course but I belive it has something to do with weather the component is more attracted to the plate or the solvent if it is more attractedbto the plate It only moves a littel uf it is attraxted to the solvent it moves alot I dont really know feel free to correct me

@hyeballer 9 лет назад

+Mercedes Malone Rf value's can help determine which spot is more polar (lower the spot = more polar)... However, TLC spots may vary due to the size and shape of the molecule. So to simply say that a spot is "more polar" because its lower isn't necessarily 100% correct.

@misssweethearted 9 лет назад

hyeballer actually Rf values tell you about the affinity of the solute to the TLC plate. A high Rf value means a lower affinity for the TLC plate and greater solubility in the solvent.

@shannondove96 8 лет назад

can chromatography work with extremely small concentration, ....for example if you're trying to separate something out that is in the parts per trillion range?

@eisenj21188 9 лет назад

why do u have to remove your plate just a little before it reaches the top and not just let it go all the way?

@maryc5905 9 лет назад

the components that you were trying to separate will end up all reaching the end and run off the TLC plate along with the solvent

@hyeballer 9 лет назад

Josh... Technically speaking, you can let it go to the top...as long as you remove it the moment it reaches the top. As Mary C stated, if you were to leave it a prolonged period the spots will continue to run up.

@theresiafeline2485 5 лет назад

I think silica is non-polar???

@ac4190 5 лет назад

Silica, (SiO2)x, is polar due to the polarity exhibited between the oxygen and silicon atoms. The silicon atoms are more electropositive than oxygen, and oxygen atoms are more electronegative than silicon.

@lina4469 5 месяцев назад

you know, it'd be real cool iof you didn't write in cursive

@BigChungusthe3rd 8 лет назад

Why does she say nonpolar molecules are attracted to the mobile phase, when the mobile phase is at the bottom? Why does it travel up higher? If someone knows and could answer it'd be much appreciated!

@meinkanta 8 лет назад

The mobile phase has travelled up the TLC plate by capillary action - the purple line she drew on the top of the TLC plate inticates how far the mobile phase moved. The less polar molecule being more attracted to the mobile phase means it moved further.

@meinkanta 8 лет назад

+Arsank47 That sounds more like Gas Chromatography?

@meinkanta 8 лет назад

+Arsank47 Okay, so your stationary phase would be the TLC plate, which probably uses silica. The mobile phase is the solvent you're using. I'm not sure about the others, but I'd guess the detection system would be calculation of the Rf values and comparing them to a database.

@BuffaloZx 7 лет назад

Usually like this channel but I don't think a simple topic could be explained with any more complexity than in this tutorial

@VirgiliusRomanus 10 лет назад

are you mentioning what happens when the solvent is polar or nonpolar??? You should. Otherwise this is an incomplete explanation.

@LilyLi33 10 лет назад

Isn't the stationary phase always polar and the mobile phase always nonpolar?

@LilyLi33 9 лет назад

AnetheronOriginal Yeah, I've learned a lot at my internship. Solvents, duh! Sorry, I'm only in my first year of high school so :P

@easylearning981 8 лет назад

+Lily Li In this type of chromatography, compounds with more affinity to the solvent will travel further along with the solvent.

@PrideofPitchers 7 лет назад

+VirgiliusRomanus She explained the polarity of the solvent briefly, but not a solvent that consists of compounds with different polarities. For example, you could have a mixture of 5 parts ethyl acetate and 95 parts hexane (hexane being nonpolar) as your solvent, which will affect the distribution of compounds on the plate. In this case, nonpolar compounds won't be attracted to the stationary silicone phase or acetate and will travel very high up the plate because of their affinity to hexane. Polar compounds won't likely move very far because 5 parts acetate isn't polar enough to break that adsorption to the silicone plating. hope that helped.

@BrokenTwistedPrince 6 лет назад

PrideofPitchers you make some interesting points, do you know anything about the affinity of aluminium backed microcrystalline cellulose thin layer plates during the stationary and mobile phase?