How can I improve my TLC plate?

How can I improve my TLC plate?

Resolution in thin-layer chromatography (TLC) can be improved by reducing the size of the sample spot and increasing the separation between the developed spots.

How would we get better separation between spots on a TLC plate?

A prep TLC is the best solution to separate out the closely present spots. Adjust solvent polarity and use a higher column. Use longer column and “very” less polar solvent, don’t increase the polarity dramatically.

What can you do if the spots are not visible on the TLC plate?

No spots are seen on the plate: You might not have spotted enough compound, perhaps because the solution of the compound is too dilute. Try concentrating the solution, or spot it several times in one place, allowing the solvent to dry between applications.

How do TLC spots change with concentration?

the appearance of two more spots is due to increased concentration as the impurities or undesirable compounds increase with increase in concentration. try increasing the concentration on TLC as u used on prep TLC and then verify the result (presence of additional spots).

What does 2 spots on a TLC plate mean?

Ideally, each compound in a mixture will produce a distinct spot so a sample with two compounds will give two different spots, and so on. An important property of any compound, is its Rf-value (retention factor). In simple terms, this value is an indication of how far up a TLC-plate a compound has wandered.

Why do TLC spots have to be small?

Spots are applied to the plate using very thin glass pipettes. The capillary should be thin enough to apply a neat spot, but not so thin as to prevent the uptake of an adequate quantity of analyte.

Why is a small spot of pigment needed on a TLC plate?

Why might not all of the amino acids known to be present in the mixture have appeared on your chromatogram? Why is a small spot of pigment needed on the TLC plate? Use a different solvent and/or a different stationary phase, this means pigments which may have run together will separate out.

How do you prevent smeared spots in paper chromatography?

When you spot samples on the chromatographic paper do it with a capillary tube and concentrate it as much as possible with successive drying of the spot you kept. You must make sure the spot you kept must be concentrated and dry enough then you may be able to witness unsmudged dispersion.

How do you make chromatography spots visible?

In some cases, it may be possible to make the spots visible by reacting them with something which produces a coloured product. A good example of this is in chromatograms produced from amino acid mixtures. The chromatogram is allowed to dry and is then sprayed with a solution of ninhydrin.

What happens if you apply too much compound on the TLC plate?

Answer: The ink might travel with the eluting solvent and separate into its component pigments, giving you a lot of extraneous spots. 3) What could happen if you spot too much of a compound on the TLC plate? Answer: The spot would show trailing. Answer: The spots would dissolve into the reservoir of eluting solvent.

How do I choose a solvent for TLC?

If you want the Rf of your TLC spot to be smaller, i.e., the spot to be lower down on the plate, you must decrease the eluent polarity. Either choose a different eluent (solvent) or adjust the solvent ratio by increasing the percentage of the nonpolar solvent relative to the polar solvent in the eluent.

How do you remove spots from a TLC plate?

The solvent level has to be below the starting line of the TLC, otherwise the spots will dissolve away. The lower edge of the plate is then dipped in a solvent.

What happens if a TLC plate is too concentrated?

If the TLC plate runs samples which are too concentrated, the spots will be streaked and/or run together. If this happens, you will have to start over with a more dilute sample to spot and run on a TLC plate. Here’s what overloaded plates look like compared to well-spotted plates.

How do you prepare a TLC plate for painting?

Preparing the Plate Do not touch the TLC plate on the side with the white surface. In order to obtain an imaginary start line, make two notches on each side of the TLC plate. You can also draw a thin line with pencil. Do not use pen.

How do you use a TLC analyte on a PCR line?

Using TLC pipettes, apply spots of analyte to the line. Make sure enough sample is spotted on the plate. This can be done by using the short-wave UV. A purple spot should be seen. If the spot is not visible, more sample needs to be applied to the plate.