TLC- Related substances test -URGENT, THANKS

[olivia929]

Flucytosine (USP)


Fluorouracil— Dissolve 250 mg in 10 mL of a mixture of glacial acetic acid and water (4:1). Apply 20 µL of this solution to a thin-layer chromatographic plate (see Chromatography 621 ) coated with a 0.5-mm layer of chromatographic silica gel mixture. To the same plate apply 20 µL, in 10-µL increments, of a 0.025 mg per mL solution of USP Fluorouracil RS in a mixture of glacial acetic acid and water (4:1). Develop the chromatogram in a mixture of chloroform and glacial acetic acid (13:7) until the solvent front has moved not less than 14 cm from the origin. Remove the plate from the developing chamber, and allow the solvent to evaporate. Locate the spots on the plate by observing under short-wavelength UV radiation:

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any spot from the solution under test is not greater in size and intensity than the spot at the respective R F produced by the Standard solution, corresponding to not more than 0.1% of fluorouracil.
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Could anyone suggest that what results could be get by this TLC for this specific impurity (Fluorouracil) ? If it is only for Fluorouracil( Fluorouracil NMT 0.1%)? It is only to compare spots at the same Rf? Not all spots obtained from test solution need to compare with the spot at the Rf produced by the standard solution????. right or not

Thanks for following post.....

[krickos]

Hi

I would do the same interpration myself as the the is named after a single specified impurity and not called TLC purity or similar.

But I agree that the text is confusing, but does refer to respective Rf.

[olivia929]

Thanks for posting, anyone detail interpretation please follow.

[Tuzcu]

Can I seperate different functional silane compounds with TLC? Is there anyway to walk the silane compounds up on the silica layer / aluminium oxide layer? I couldn't find any reference explaining this.
Thanks in advance,

Gozde