A Practical Guide to TLC (Thin Layer Chromatography)
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- Опубликовано: 2 авг 2024
- In this video, I discuss the
/ thatchemist
Community Discord - / discord
My AgNO3 stain (0.2 g AgNO3, dissolved in 10 mL H2O, 10 mL MeOH). It isn't too light sensitive - it will form a slight black precipitate, but this doesn't affect the quality of the stain). This stain is good for sulfur derivatives.
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Links to articles discussed in this episode:
Great solvent group guide -www.yumpu.com/en/document/vie...
NotVoodooX- www.chem.rochester.edu/notvood...
A list of good stains -
www.chemistry.mcmaster.ca/adr...
Seebach's magic stain:
25 g polymolybdic acid
10 g cerium (IV) sulfate
60 ml conc. H2SO4
940 ml H2O
(from) www.scripps.edu/baran/images/...
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How about 2D TLC, extremly usefull if you are not sure if al compounds are seperated.
I learned it as a way to test if your compound is degrading on TLC. If everything is on the diagonal after you've run it a second time, then you're good. If not, your compound might be decomposing on the plate
Also, you can run two different solvent systems then and even change the pH to have incredible resolution
Yes a video on 2D TLC and Prep TLC would’ve been great too!
Rookie mistakes
-do not use pen to mark your starting lines as they can create additional spots
-be really gentle when disposing the tlc plate in the eluent beaker as you can easily cause a crooked separation
-Draw your solvent front line as quick as possible, solvent front evaporates = impossible to calculate RF.
-don't ever use a plastic ruler to draw your solvent front, RIP my ruler D:
We all have THAT ruler in the lab
When I cut my TLC plates, I always draw the frontline ahead so that I know when to pick up and it also helps the Rf calculations more consistent most of the time.
I've heard it reasoned that a good organic chemist is necessarily a good (or at least proficient) analytical chemist. In the transition from chemistry as an art to chemistry the science, systematic collection of data is the main driver of discovery. The only way to tell, 100%, what on earth happened to a reaction when a parameter is modified, is using modern analysis. And if progress is a road, it is not the reactions themselves, but the TLC plates of them that are the paving bricks.
In the old days, we made our own tlc plates using microscope slides and silica slurry.
"1mg" "small". As a pharmacologist I'm always amazed by the massive quantities chemists always use! Most of my entire sock of a drug I'll order will be only a couple of mg total, and that will usually cost an equivalent of ~1,000 USD. Really interesting video none the less!
One tip to improve resolution is to add just a drop of water to the eluent, it makes the bands more sharp and defined. I can really recommend this for stuff that isn't super water sensitive, it's kind of the opposite of using TEA.
Interesting
Old tech: Can visualize dried TLC by "iodine chamber" (closed container with an iodine crystal. Brown spots where compounds. Circle with pencil because the Iodine evaporates away.
yeah it works well sometimes!
Staining with iodine followed by a dip in water enhances weakly seen compounds.
In my experience with TLC, it’s best to avoid chasing waterfalls. Just stick to the rivers and the lakes that you’re used to.
but you should test out solvent groups - especially if you do methods chemistry, and have some weird functional group or heterocycle
When I was a work-study at my undergrad the TLC cutting was jokingly called grunt work and usually the underclassmen had to do it.
I will be happy to never have to cut TLC plates again.
We used an office paper trimmer to cut Al backed plates
This is a weird tender, love and care video.
My favorite is Bromocresol green. Because it let me figure out a problem in our plant. Simple TLC could help me monitor the process in minutes rather than the 30 min run time for GC, and allowed me to conduct quick analytical tests on vendors solution at their site before bringing it back for the full analysis.
Based on my previous lab experience, we used pencil to draw the start and end line（never create new spot ).
Using a paper cutter to cut aluminum TLC, it is very convenient to quickly cut a large number of sheets.
Wonderful video with lots of great tips! TLC is often extremely underrated along with being easy to learn but hard to master. What has to do with the strange values called solvent strength - it is a measure of a solvents ability to elute a compound from a given stationary phase, i.e. generally speaking, the higher the value the quicker the compound will elute. One can also notice that the tables of solvent strength are reversed when comparing normal and reverse stationary phases (for example, water has a big solvent strength on silica but low strength on C-18 with the reverse being true for hexane). It is also my understanding that solvent strengths assume that a compound is properly soluble in a given solvent.
P.S.
I had a very wholesome TLC experience with an undergrad student once. I explained to the guy how to properly perform a TLC and let him do it while I went for a lunch break (we use aluminum-backed plates, not glass). When I returned back to the lab the dude showed me how things went which caused my mind to ascend to a higher dimension for a few seconds lmao. What happened was - the plate that the guy chose to use was too wide for the TLC chamber and so instead of finding a bigger chamber or cutting the plate he bent the plate down the middle at a 90 degree angle and shoved it in the chamber XD. I bought the undergrad a beer after that for making my day :))
Haha
dude just as I think your videos cant get any better you surprise me again, this is the best chemistry channel in youtube, keep up the good work!
Wow, thank you!
I had no idea glass plates were actually used for standard small sized TLCs! We only use the 0.5 and 1 mm thick silica layered ones (around 20x20 cm length and height) for preparative TLC purification of smaller samples. And even that has been annoying lately, since our supervisor has been getting on our case about them being too expensive.
About the chipping of the silica and the scissor thing, it used to happen to me all the time when I was an undergrad, but I can't remember the last time it happened. Don't know if its just a matter of getting the hang of it, or just having the right coice of scissors haha
I did something similar to a TLC in high school. We took card stock and made marks with a bunch of different sharpie pens in a row (different brands but same color). Then the professor made a final mark in secret with a mystery brand black marker. We then placed the end of the card stock with the marks in a shallow amount of a solvent. The solvent crept up the card stock via capillary action, and took the black marks with it. The interesting thing was that different solvents carried different dyes different distances and you got a unique color pattern for each brand of black marker. We could pretty confidently identify which brand the mystery marker was. In theory, you can even determine if an unknown marker was made in the same batch as a known marker. I'm fairly certain i used acetone for my solvent, but water alone also worked to a certain degree with water soluble markers.
I believe the professor got the idea for this lab from an experiment that forensic chemists either did or theorized.
Yeah that’s a great intro experiment
One of the weird systems that works for me, when the compound is somewhat polar is DCM:EtAcO. It makes my life easier to introduce the sample, since dcm actually dissolves stuff. If I see that i need a 1:1 pentane:EtAcO, I would usually try my luck with 9:1 DCM:EtAcO and avoid dealing with celite.
iodine chamber is good for detecting grease and ""grease""
if nothing shows up it can still be followed up by a permanganate stain
Toulene + MeCN is also something I heard being used
cutting tlc places tho! it took be burning through a good 20 plates before i got my first one which was perfectly broken with every plate!
Great and very informative video, thank You! The solvent group strategy seems genuinely very useful.
One simple thing not mentioned is keeping a piece of filter paper in the elutent jar to saturate the air inside withe the solvent. Something I have always done. There is some good stuff about tlc and chromatograpy in Leonatd and Lygos book "Advanced Practical Organic Chemistry." I picked up many useful lab techniques from that book many years ago, have the 1995 edition.
Something that lasts a bit longer than capillary is a simple needle. Just snip the end off and form it to your liking with pliers. Imo it's much easier to clean and reuse without breaking while still getting super fine spots if using a thin needle. Obviously just attach the needle to the end of a syringe to make handling easier.
Edit: Ah and since KMnO4 is the most popular stain (sigh), you can also wash the unstained portion of the TLC plate to make it exponentially more readable. All you need to do is after staining with KMnO4 and drying with heat-gun, place TLC plate in a vial full of water. Leave for a couple of seconds and all the stain that hasn't reacted with analyte will wash out while the stained portion will remain, then dry the plate again with heat-gun. Careful with the heat setting as the silica tends to crack after it's been in water.
Btw: this is the first time I see glass-backed TLC plates for non-preparative use, how common are they? Seems like a pain to work with compared to the aluminium-backed (I guess it's Al) ones I'm used to. We NEVER used scissors to cut them though, they tended to crack, we always used box cutters.
Yeah I tried this, but I always found that it scratched the silica - with my glass capillary, I always flamed the end so that it would be smooth
@@That_Chemist Is the silica on those glass-backed plates also kinda soft and powdery like the preparative ones? I've never had experience with them, though I get what you mean with the sound of cutting the plates freaking you out, I have the same thing with the sound of a permanent marker writing on paper (makes me sick just thinking about it).
Melting point capillaries are a good alternative too, I feel like they're a little more durable than Selfmade ones
@@banyi4068 That was my alternative as well, but they're always too thic for me so I resorted to melting the tip and stretching it out a bit to thin it out. But they only lasted a week max for me.
@@janvisagie231 I’ve worked with both and I definitely prefer the glass-backed one vs the other type. I’ve noticed the glass supported ones are soft too but less flaky/powdery in comparison so they stick better to the surface & are more durable when using a pencil to write & draw lines on it. The other type is sometimes too flaky where even pressing gently with a pencil scratches off the silica. The downside with glass is that it’s heavier obviously and also easier to break if you accidentally drop it whereas the other one doesn’t break if you drop it but may lose some Silica from flaking off in my experience.
Nice video!
In the lab, we are using mostly just three stains - KMnO4, vaniline and PMA (Phosphomolybdic acid). Love vaniline and PMA, they are making various colours to better identify products/sideproducts. And the smell of vaniline - like christmas cookies :D
For the purification I am using most of the time gradient hexane/EtOAc. Also very interesting mobile phase is DCM/acetone. Using this after Mitsunobu reaction, because H2DIAD has same Rf as product in hexane/EtOAc.
Back in the day I did a bit of work with fatty acids and their derivatives. We used to "stain" our TLC plates by spraying them with a light misting of water. The water would dry from the hydrophobic compounds first so you could see where they were on the plate. We'd then follow that up with UV and then an iodine chamber to make sure we visualized everything on the plate.
Alumina also used for tlc plates.
Thanks a lot for this video! I think these kind of videos on practical lab techniques are very rare on youtube but they actually help a lot. No paper ever mentions the struggles people had on finding the correct column solvents or on performing the best work up whatsoever, and you can hardly find any practical text book on these things. These tips and tricks one can normally only learn by practice in different labs, but nobody can visit all possible labs in this world to learn every single "lab life hack". That's why I would definitely keep watching your videos if you continue creating this kind of great content!
Thank you :)
Greetings from Germany!
Guten tag!
Love it! Keep it up! Could you make a video on how to manage time in graduate school? (e.g., Getting reactions in while keeping up with literature and leisure time). I seem to struggle with keeping up with literature and find myself only doing reactions in the lab some days.
Also a tier list on C-C bond forming reactions
Cheers
I was waiting for the ninhydrin mention. It's great for amino acids.
I recently tried a couple tlc runs and didn't even get migration on most of the samples.
It sounds so simple, but it's very tricky to get right.
When cutting glass-backed plates, if you turn them silica-side-up on top of a couple layers of paper towels, you can press gently on the center of the plate, and cause the scored lines to "run", cracking the length of the score easily, no worries about potentially cutting yourself while trying to put pressure with your fingers.
One of my favorite tools for cutting TLC plates is a quilting ruler. They're larger, usually several inches wide (also available in metric) and measure in both length and width. This is great for making sure your ruler is aligned square with the edge of the plate, so no need to mark repeatedly to get straight lines along the width of the plate to make sure your lines are straight. My current lab quilting ruler is 5 cm wide and 15 cm long. They're also a bit thicker than your average ruler, so more protection if you want to cut aluminum plates. I use a quilting ruler for that and a snap-off blade. Works wonders! I'd prefer glass, personally, but my PI has an old stash of aluminum plates...
That’s a good idea!
Great video, lots of good tips. I actually enjoy cutting glass tlc plates. As you know they (mostly) come as 20cm x 20cm squares. I use a Sharpie to make dots on the top and bottom edges at 5, 10, and 15 cm then line up the ruler to cut the plate into four 5 x 20 strips and snap them out. I then cut smaller plates from the strips using a ruler as a guide, but I just eyeball the width. Some I make narrower for analysis, and some wider for analyzing flash fractions. As you say, breaking them cleanly is a matter of practice, but it's impeditive to start with a good cut. When the cutter makes that certain ripping sound, we know it's going to be an easy snap. I'm not going to say that I lick the diamond before cutting, but let's just say a little lube seems to help make a good cut.
When spotting a tlc plate I don't bother drawing a line; instead I just push the capillary into the silica slightly to make a little divot that can be seen later. When taking the plate out of the developing chamber using tweezers, one can quickly nick the silica gel at the solvent front. Usually drawing a line isn't necessary unless you actually need to calculate the rf.
As far as stains, the ones you mentioned suffice for almost all cases. I've never had much success with I2, so I gave up on it. One system that works well for peptides or other weakly nucleophilic compounds is tollidine/KI. It's a two step stain; the first step requires a few minutes in a chamber containing Cl2 (easily made by mixing dilute HCL and some bleach in a vial, inside a developing jar. Make it in the morning and it'll last all day) This treatment converts N-H to N-Cl. After airing the plate out for a few minutes, it is them dipped into the tollidine/KI solution; spots show up as dark purple. It's quite sensitive.
I really love your videos! Amazing quality
Thank you so much!
very interesting video, i'm very interested in seeing more of these begginer friendly practical lab guides , thank you
:)
I really like CAM. It’s permanent and stains almost anything.
I second that. Plus it's super sensitive.
using 1% of formic acid helps the smearing on the plates, even for the flash with compunds having alcohols in it.
Great video, please make more video about lab stuff! (things like making capillary tube, best ways to remove solvents like HMPA, how to store deuterated solvents,...)
Nice thing about diethyl ether eluent is that it evaporates off very readily.
true
Undergrad story:
I was running a column on this compound, using the standard EtOAc/pentane mixture, getting good separation - but somehow when running the column the spots came out in a different order from the TLC! As I was sampling my column fractions by TLC, the spots came out in the order 1 - 3 - 2.
I had no idea how that happened. Did I switch the fractions up? No, it was all right all there...
So I ended up switching to a DCM/heptane mixture instead, and that's the mixture we ended up publishing. Later the PhD who was mentoring me, when looking over the experimentals I was submitting, asked me how the heck I ended up with DCM/heptane mixture. Just undergrad things. ¯\_(ツ)_/¯
sometimes that does happen - I've had it happen once or twice
TLC plates are usually left open to the air, and thus the silica is saturated with water of hydration. Silica for columns is more likely to be anhydrous. Might make a difference?
One thing you only sightly glossed over: adding 1-2% Et3N can help separating pH sensitive groups like acids and amines. It can also greatly reduce smearing for some compounds.
Just don't use with KMnO4 stain though;)
Adding a squared filter paper into the TLC well will make the solvent run much fast, helps alot when you're running alot of TLC's.
For the alumina plates, it's very important to keep them as dry as possible or they will crack. We keep ours in a box with dessicant and don't precut more than 2-3 sheets at one time. Also cutting with a scapel is superior to scissors as they tend to flake much less as you only need to cut with pressure from one side.
Glass plates are so much more annoying to use and make, using the undergrads as labour is good idea though haha
great video, I would like to see more of these
Thanks!
@@That_Chemist Maybe a Video on different types of chromatography would be nice too. But I am sure you have plenty ideas already.
Great explanation
:) thanks!
Very useful video. Keep it up!
Thanks!
Nice video, thanks a lot! Hope to watch one on recrystallisation, I have more experience in chromatography, would like to improve my purification through crystallisation skills!
Growing crystals is definitely a skill as well as an art
I use sulfuric acid solution, or ammonium molybdate in methanol, for cholestane derivatives, and the classic Hex:AcOEt, but...Figueroa's solvent system is interesting, it could be used from preparing soups to separating 50 different compounds on a single plate, because it contains Agua. Great Channel and videos.
Thanks :)
I’d recommend KMnO4 with alkynes vs alkenes don’t heat yet. Alkynes will show without heat. Also metal impregnated TLC plates will help with separating non polar compounds but differ by alkyne vs alkene or alkane. Usually CuI
One issue with acetone is many people will use a less expensive reagent class containing water which depending on amount of water produces variable results. Also, since acetone is so hydroscopic, it rapidly gains waters of hydration from atmosphere.
I need to try the infamous Figueroa system next time I do TLC
Lol. There’s no way that works right? I’ve seen and used some exotic components for TLC solvent systems and even done 3 component solvent systems which is even more rare for some separation of compounds but I’ve never seen anyone use water as a component for the solvent system in TLC. If you do actually try it, please let us know as I’m curious to see if it just screws up the silica gel with TLC and column chromatography.
I love and hate TLC because it is so flexible.
As a teacher I cant go and buy all the obscure solvents for ind experiments and I usually dont have time to test the many combi nations used in litterature.
Thanks for the advise regarding limiting to ethyl acetate / hexanes. I will try that.
I work with a lot of really aromatic systems the do a lot of pi stacking so they are quite insoluble in hexane:ethyl acetate mixtures and I get really wide bands off my columns.
I have to do lot of toluene:DCM columns which I get tight bands with but rotovapping fractions afterwards takes ages
I hate silica gel. It's coarse and rough and gets everywhere.
A video about metrics for journals, researchers and articles would be super interesting!
He plans to make a series related to the idea of journals, publishing, impact factors, etc. I agree though other metrics besides impact factor should be included too.
My professor talked to me about what it was like making her own TLC plates back in the 80's and 90's. She said her professors were really cheap, and she had to make plates for the whole school, along with capillary tubes from pipettes. She says she still has glass in her hand from that.
It used to be very common that people made their own TLC plates because you can indeed save a lot of money if you reuse the glass plate. I made alumina prep TLC plates once because we had the supplies to make it (the bottle of alumina + binder was probably 20-30 years old) and ordering it would take way longer. It was rather easy to get a nice plate and didn't take too much time.
making capillaries is fine - its often easier to make a small capillary from a wider piece of glass
@@mathiasdaniels651 when I used the glass prep plates I saved them to make homemade prep plates which came out pretty good. Good technique to have I would say
Someone needs to send this to extractions and ire for his cubane series he's having some trouble with TLC
I agree with most of what you said, but silica on Aluminium is far more convenient. Just get a heavy duty paper cutter (ours was like 70$), and never have any large chunks of silica break off the edges. I always run my fingers along the edges to make sure all the silica that’s loose comes off and never had any issues with crooked solvent lines. Always having to break glass is just a hustle and I imagine the plates are a hazard as well since they’re sharp as hell.
TLC is a great technique. I usually use rf 0.25-0.3 for a manual column and rf 0.1 or so for an automated flash system if the separation is good. DCM:alkanes can also give good results, especially if you work with polycyclic aromatic compounds as they usually have better solubility in DCM or chloroform (and you can use a larger concentration of the "good" solvent in alkanes)
Great tip!
Automated chromatography can utilize gradient elution which optimizes separation. This is better than isochratic elution.
@@campbeja001 That is true but usually only done in a industry setting or labs with a rich PI/very well funded by grants and collaborations with companies anyways. Most academic labs at a university rely on old-school classical manual glass columns to perform column chromatography so using automated systems is more of a privilege. I also highly doubt that anyone who uses automated chromatography systems wasn’t at one point first introduced to manual column chromatography to first learn the technique/fundamentals prior. You’d be a very lucky person if automated was the first time you learned about & conducted chromatography.
@@uiucchemistry2664 I only mentioned this as the OP specifically mentioned using automated chromatography. Regardless, if manual or automatic, gradient elution on chromatography columns most often achieves faster and higher band resolution than isochratic elution.
@@campbeja001 Ah okay. Yeah I missed that small word in the OP’s post. Gradient is always better though sometimes not always needed depending on how easy or clean the reaction was in terms of products formed.
Shoutout to Bromocresol Green to visualize acidic substances like carboxylic acids!
Capilaries seem disposable until you get one that works really well and you never want to throw it away
Absolutely!
Damn, so many new videos :o Do you even sleep? Nice presentations nevertheless ^^
Thanks
Idk about anyone else, but I’m always floored by how many people have….superstitious and very weakly supported ideas about methanol being incompatible with silica above 10% conc. I have USUALLY had to run tlc and columns with DCM/MeOH with methanol percentages ranging from 20-80%. It has NEVER affected my purity or separation or had any silica “dissolve” into my collection flask
If you do that though, you need to collect the eluent that flows through the first bit, cause the small silica particles are mobilized
@@That_Chemist well sure, I mean I usually run a gradient and the loose silica that is too fine will come off first.
My man really sleeping on sulfuric acid stain, used in the entire carbohydrate chemistry field.
Vanillin is the same, but slightly better in my experience
I found that an Rf of 0.2 was best for columns as well.
Awesome
Informative video - thank you! I was hoping for some explanation of the role of the solid phase and how it interacts with organic moieties. Are there alternatives to silica - maybe alumina or other metal oxides?
Yeah alumina is common, and you can also do reverse phase silica
My first TLC: I put the samples on the shiny side of the card and wondered, why it didn’t work..
Hahaha
14:43 not a chemist, but a computer scientist :/ also not an undergrad, let alone high school student.. just interested in learning about all the sciences. Not stepping foot into any lab after seeing your vids lol!
haha
My first and only TLC so far simply didn't work.
In my highschool class, we tried using TLC on different amino acids (pure samples in ethanol, not exactly new but of good quality). The eluent was (by mass) 2:1:1 acetone, 1-butanol, glacial acetic acid. Knowing how TLC generally works, I expected something like hexanes in there but our textbook suggested this exact eluent mixture. We did everything as the procedure asked us to do, then applied a ninhydrin staining solution but all our spots simply stayed on the starting line, they didn't move at all.
unprotected amino acids are not well-suited for TLC on silica
@@That_Chemist So they just bound to the silica? That information comes about half a year too late but it still is good to understand why it failed. The authors of my textbook really believed that would work.
I used 1 capillary for every column for about 2 years, lol
Yeah, a good capillary is precious
Should probably also mention that for some compounds TLC just simply doesn't work well. In our lab internship we had to purify a benzylhydroxylamine derivate via flash coloumn and it just ate our product on the plate (we had product confirmed with nmr)
Rip
O-alkyl hydroxamates bond strongly to stationary phase. Requires solvents of high polarity to elite them (ie-5 to 10% MeOH/DCM to elite in many cases)
@@campbeja001 yeah we learned that the hard way😂. We did put it through a coloumn eventually but couldn't go above 3% MeOH. It took 120 fractions (20ml each) to eventually get it through
@@maxmuenchow Did you try using deactivated alumina?
@@campbeja001 I wasn't even familiar with that but reading up on it it seems like a a sensible approach. It was just a 3 week internship but I think I'll send it to the phd student I was working for. Thanks 🙏
Some people emphasize the need for activating the plate in an oven or over a hotplate prior to use. I think this is too time consuming so I just keep mine in the dessicator over NaOH for at least 24 h after cutting them, but maybe I should be more careful.
I have literally never done that ever
Are you going to do these for other tests? Like HPLC?
(You might already have a guide on your other channel, apologies if it’s my lack of looking)
I will definitely do some on flash chromatography / using a combiflash, but I haven't done very much HPLC
@@That_Chemist ok fair enough, these videos are really useful for people who are in the education system, not as replacements of course, but just as generic ways to familiarise oneself with the processes. This would also be good for someone going for a job interview who hasn’t done these tests for a while and prefers a video refresher rather than reading about the processes in notes. Lots of potential here with these guides.
@@That_Chemist Yes a video on column chromatography & combi flash would be excellent!!! It’s a natural follow up to your TLC video. Dry vs Wet loading your compound, silica slurry method for column packing or dry SiO2 gel method for column packing, using sand/cotton balls/glass frit/Na2SO4 as a small layer to absorb any remaining moisture when doing columns, flash vs gravity columns, SiO2 gel or Alumina, spiking columns with AcOH or NEt3, isocratic or gradient elutions (if gradient, then how much to jump by % wise without cracking the column from 10%EA/Hex to 60% EA/Hex for example), do you recommend solvent reservoirs to hold more solvent thus requiring less frequent solvent prep for longer columns, etc. I gave you a million ideas for all the nuances & probably others I’ve missed where people can add from their own experience so I’d love to see a video on it!
It is a pity you did not mention a very common issue, namely, compound dragging through the TLC plate (and a column as well)
Anisaldehyde is the best smelling stain
but it is toxic :(
Can you do a vid on recrystallisation? Literally the bane of my existence in my undergrad research
its really more of an art - I would need to do a bunch of labwork and record stuff, but maybe at some point yeah
Al plates are easier to cut with razor blades
I've been taught about 2D-TLC as a method for tricky sepratations but I don't think i've ever seen anybody actually do that outside of just doing it for the sake of it.
Have you ever used that technique in a serious setting?
Would you even ever want to use it for an application like this considering the obvious practical drawbacks like having to use separate plates per sample?
What do you think about commercially availabile capillaries?
Nice to have but waste of precious funding once you've gotten comfortable making your own or are there other practical reasons?
For 2D TLC, I've only used it to check if stuff is decomposing on silica
For capillaries, I just find that I have much better control at making a really narrow capillary if I pull them myself from a glass pipette - you can also make a nice handle for the capillary from the pipette
The link to Laboratory Chromatography Guide only contains a part of the book (30 pages). Where did you get the rest of it - it should be 125 - 130pages ?
That’s all I have
Would you have any interest in making a video on advices or tips when looking for or choosing a PI? There are so many people who end up in bad PI relationships. I had 2 lol.
Yeah I might do this at some point
So...Dihydropyran when analyzed on TLC(EtOAc/Hex 8/2) gives more than one band, albeit not UV active and we've always learned that the TLC shows one spot for pure compounds. So are compounds such as, Dihydropyran and benzylidene aniline the exception??? If so, why?
ask in the discord!
10:31
Work those goblins
Hey, is there a video or list for the scientific background you have. I am just wondering what resources you had for your education and so on. Hope this question is possible to answer without compromising your privacy. Thanks in advance.
Ask ppl in the discord
ninhydrin gang
How to separated Benzoyl chloride and benzoic acid especially for p-nitrobenzoic acid and p-nitrobenzoylchloride?
Any suggestion?
Distillation
@@That_Chemist
Sir i asked for TLC separation
Most common mistake for running a TLC:
1/ Drop the damn plate in the TLC jar. Sometimes still fixable by picking it up quickly…
2/ Drop the developed and stained TLC plate on the dirty lab ground. And most of the time, the plates always kinda want to pick the silica gel face to land on 😭
3/ Put the plate and leave for toilet or chit chat. Come back and find out that the spot may have had travelled up to the ceiling 😂
Not a mistake but sometimes I do get some spots with “interesting” shapes (skull, d*ck, headphone, screaming face, smiley face, sad face, etc.) 😅
Is there any way to visualize the phosphor in the components through TLC ?!
there is TLC-MS, so I don't know why there wouldn't be TLC-UV-VIS
or TLC-Fluorometry
@@That_Chemist how is that ? Can you explain more ?
www.emdmillipore.com/CA/en/analytics-sample-preparation/learning-center-thin-layer-chromatography/tlc-ms/D3Cb.qB.FycAAAFVpvlDx07P,nav?ReferrerURL=https%3A%2F%2Fwww.google.ca%2F&bd=1
Food/booze for thought for anyone who is a homebrewer and/or working with highly polar compounds:
I've used a janky-but-effective type of TLC in homebrewing to figure out what sugars my yeast had consumed at various points in fermentation. First I bought cheap 2.5x7.5 cm Al-backed silica plates on eBay, then spotted my starting wort and/or fermenting beer onto the plate with a $35 micropipette from China. The most effective solvent mix I tried was of course highly polar: 85% IPA, 15% H2O. 80% acetone also worked decently well. I used a beaker with a watchglass, and it took about 20-25 min to be done. For visualization, I used a spray of 5% phosphoric acid in ethanol and stuck it in a toaster oven at about 100 C for 5-10 min, making nice brown spots. Glucose, maltose, and maltotriose all separated very well and I could usually see DP4 and DP5 spots too!
If you want to test this out, optimize the water percentage, or make a ladder of glucose oligomers alongside the wort/beer, dilute 5% corn syrup in water and spot that onto a plate. Corn syrup contains various short dextrins and can give you a nice clean source of them to see how well the separation is working.
ok, hexane and methanol or water do not mix, so this will not work!
Special mention: if you are Figueroa 😀 😀
Figueroa 😂😂😂
Pro tip for aluminum backed plates: Use a metal ruler and box-cutter to gently score the back of the TLC plate. Then just gently bend it back and forth to break it off cleanly. Cut to size when you need them. No need to have stacks of pre-cut glass TLC plates lying around.
Interesting
@@That_Chemist I used to hate them too until I started using this method. Now, I love them. BTW you should do a video on different TLC media.
Another tip for cutting aluminum plates with scissors; angle the scissors a few degrees clockwise when cutting (assuming right-handed scissors and chemist). For some reason it makes a big difference in avoiding separation.
those are the ugliest tlcs ive ever seen lol
Hey >:(
I don't know if you allow links in the comments but here's a very exhaustive list of stains I found some time ago.
www.epfl.ch/labs/lcso/wp-content/uploads/2018/06/TLC_Stains.pdf