How to run a two-dimensional TLC
- Get a square TLC. : Cut a TLC plate with the shape of a square, around 7×7 cm is fine.
- Spot the sample in one corner. : Spot the solution of your sample in one of the corners of the square, leaving around 0.5-1 cm from each of the two ...
- Elute the plate in one direction. ...
- Elute the plate in another direction. ...
- Analyze the results. ...
How does the process of TLC work?
The process of TLC works via the property of polarity, or the difference in electron density across a molecule. The basic workings of TLC is that molecules that have more polarity, or have a greater difference in electron density across the molecule, will move slower than and molecules with less polarity.
What is the best way to prep for TLC?
There are commercial TLC plates made specifically for prep TLC. They are usually made of glass coated with a thicker layer of silica gel. Then, instead of a single point spot, you apply the solution of your mixture (in roughly 0.5-1 mL of a volatile solvent such as DCM) along a line, parallel to the bottom (around 3-4 cm above the bottom).
How do you make a TLC plate?
Get a big enough chamber, and make a bed with sea sand at the bottom (about 2 cm is enough) Then, put your eluent in the chamber covering just a bit above the sea sand, and stick all the TLCs you need on the sand! They will not fall, and you can elute many of them parallel to each other. Do you develop the TLC plate all the way to the top?
What equipment do I need to perform a TLC?
The equipment you'll need to perform a TLC is a TLC plate and a developing chamber. The developing chamber can be constructed with a beaker (big enough to fit the TLC plate), a piece of filter paper, and a watch-glass (big enough to cover top of the beaker).
How do you perform a TLC test?
A TLC plate is a sheet of glass, metal, or plastic which is coated with a thin layer of a solid adsorbent (usually silica or alumina)....Thin Layer Chromatography (TLC)Step 1: Prepare the developing container. ... Step 2: Prepare the TLC plate. ... Step 3: Spot the TLC plate. ... Step 4: Develop the plate. ... Step 5: Visualize the spots.
How do you run a TLC plate?
0:246:11How to Spot and Run a TLC Plate - YouTubeYouTubeStart of suggested clipEnd of suggested clipAt the bottom of the plate. Put it in the TLC chamber and the solvent will climb up by capillarityMoreAt the bottom of the plate. Put it in the TLC chamber and the solvent will climb up by capillarity by climbing up it will drag your spots up the plate according to their polarity.
What is needed for TLC?
There are little materials needed for TLC (chamber, watch glass, capillary, plate, solvent, pencil, and UV-light). Therefore, once the best solvent is found, it can be applied to other techniques such as High performance liquid chromatography.
What is the procedure of TLC plate preparation?
Plate preparation They are prepared by mixing the adsorbent, such as silica gel, with a small amount of inert binder like calcium sulfate (gypsum) and water. This mixture is spread as a thick slurry on an unreactive carrier sheet, usually glass, thick aluminum foil, or plastic.
How do I check a TLC plate?
How to prepare a TLC plate:A horizontal line is drawn at the bottom of the plate (5-8 mm from the bottom edge) and another horizontal line is drawn at the top of the plate (8 mm from the top edge). ... Vertical ticks are drawn on the bottom line, depending on how many samples are analyzed.More items...•
How do you run a 2D TLC?
To test stability of your compound on slice, run a 2D TLC:Using a square silica plate, spot the sample in one corner.Run the plate in one direction (all components of the sample will appear in a vertical line of spots).Turn the plate 90 degrees (your "line of spots" should be at the bottom) and run the plate again.More items...
How does a TLC spotter draw up and dispense sample?
To Use a TLC SpotterPlace a small amount of your sample (2–5 mg) in a clean vial or beaker.Dissolve in suitable solvent (1–2 ml).Hold the narrow end of the spotter in the solution and let the solvent be drawn up into the spotter by capillary action until the thin portion of the spotter is 3/4-full.More items...•
How to spot TLC?
Spot the TLC mixtures at the corresponding mark in the line above the bottom of the plate. Then elute the plate and see how many compounds there is in your mixture, and how polar are they, just by checking out the different spots. Try to spot your mixtures as tightly as possible. Make very small spots of sample.
What is TLC in chemistry?
If there is one technique or experiment that every chemist, or student learning chemistry should know, it is Thin Layer Chromatography (or TLC for short). If you want to become a synthetic chemist, or you are planning to ace an experimental course on organic chemistry, TLC is something you really need to master. TLC of black ink.
How high is a thin layer chromatography plate?
Usually, a thin layer chromatography plate is around 5–7 cm high, and a line is drawn around 0.5–1.0 cm from the bottom. That is the line in which you will spot your mixtures to separate. It is important that you spot the mixtures above the solvent level on your elution chamber!
How many plates of reaction crude should be run before chromatography?
It is not uncommon to run 3-4 TLC plates of a reaction crude (even for experienced chemists) before starting a flash column chromatography purification. And that is pretty much what you really need to know to perform a TLC experiment.
Can you run a TLC if you can't see the spots?
There is no use in running a TLC if you cannot see the spots of the different compounds on your mixture. That’s why having access to the appropriate visualization technique is a must.
Is TLC enough for flash column?
Sometimes TLC is just not enough and you don’t know what compound/product is in each of the different fractions that came out of your flash column. Evaporating everything and taking an NMR is really time consuming, so you might want to go for an alternative technique if it’s available to you.
Can you have two compounds in TLC?
If you have two compounds that are very close together in Rf, this might not be enough. Having two compounds show as two separate spots in TLC doesn’t mean that they will come out separately from flash column.
How to dry a TLC plate?
Dry the TLC plate. Simply set the plate down and wait a minute or so for the solvent to evaporate off the plate. You cannot run the plate if there is still solvent. You will be able to see a wet spot on the plate if there is solvent. You need not wait long for such volatile solvents as ethyl acetate and hexane.
What is TLC in chemistry?
In chemistry, thin layer chromatography (TLC) is a cheap, fast, and efficient way to separate a mixture into its components for analytical purposes. Chromatography uses a stationary phase (usually silica,alumina) and a mobile solvent phase to separate compounds. In the case of TLC, glass plates are coated with silica and then solvent is allowed ...
What are the sides of a TLC plate?
There are two sides to the TLC plate. A silica side and a glass side. The glass side is just smooth reflective glass, and the silica side is a powdery white substance that will flake off if you disturb it. So be careful when handling these plates so as to not ruin the silica gel.
How to get a TLC plate to rise up?
The solvent will rise up the TLC plate by capillary action. Make sure the solvent does not cover the spot. Allow the plate to develop until the solvent is about half a centimeter below the top of the plate. Remove the plate from the beaker and immediately mark the solvent front with a pencil. Allow the plate to dry.
How does a TLC plate work?
The TLC plate is then placed in a shallow pool of a solvent in a developing chamber so that only the very bottom of the plate is in the liquid. This liquid, or the eluent, is the mobile phase, and it slowly rises up the TLC plate by capillary action.
What is the purpose of TLC chromatography?
Since TLC is a much faster procedure than column chromatography, TLC is often used to determine the best solvent system for column chromatography.
How to make a TLC chamber?
Step 1: Prepare the developing container. The developing container for TLC can be a specially designed chamber, a jar with a lid, or a beaker with a watch glass on the top (the latter is used in the undergrad labs at CU). Pour solvent into the chamber to a depth of just less than 0.5 cm.
What is a TLC plate?
A TLC plate is a sheet of glass, metal, or plastic which is coated with a thin layer of a solid adsorbent (usually silica or alumina). A small amount of the mixture to be analyzed is spotted near the bottom of this plate. The TLC plate is then placed in a shallow pool of a solvent in a developing chamber so that only the very bottom ...
Why can't you see spots after a TLC plate is developed?
If the solvent level in the developing jar is deeper than the origin (spotting line) of the TLC plate, the solvent will dissolve the compounds into the solvent reservoir instead of allowing them to move up the plate by capillary action. Thus, you will not see spots after the plate is developed.
How big are TLC plates?
TLC plates used in the organic chem teaching labs are purchased as 5 cm x 20 cm sheets. Each large sheet is cut horizontally into plates which are 5 cm tall by various widths; the more samples you plan to run on a plate, the wider it needs to be. Shown in the photo to the left is a box of TLC plates, a large un-cut TLC sheet, and a small TLC plate which has been cut to a convenient size. Handle the plates carefully so that you do not disturb the coating of adsorbent or get them dirty.
