Dear all,
Does someone know how to interpret a TLC plate? I wanted to detect polyphenols and flavonoids in plant extracts. What I did it was to spot some drops of sample, quercetin and gallic acid in a silica plate and see how they elute (elution with isopropanol). After, I added AlCl3 solution to see the flavonoids and FeCl3 for the polyphenols. In the pictures is posible to see the plates with the two stains under normal light and under UV 365nm.
Thanks in advance
I am not sure if I get your question. Your TLC plate looks not that god. You have to use a better elution solvent mix. The smear might result from overloading.It seems that no quercetin is in your sample, but pure aglycons are quite rare in nature. From the very colored band of your sample, I would suggest that you have a lots of different phenolic acid derivatives and flavonoid derivatives in your sample (most of them will be glycosides).
However, flavonoids are polyphenols. "Real" polyphenols, I would mean poly-polyphenols such as tannins or similar ones, won't separate very well on TLC.
Thank you for your answer Sascha. It is the first time I work with TLC so I do not know how to interpret the results in a proper way.
For your first approach, this looks quite good ;-)
Although, TLC is kind of robust, a good clean-up is very helpful to get sharp, well separated bands...the rest is easy...at least every stainig reagent will give an information about the properties/presence of substances...Rf is one thing, but it is never a 100%proof that your substance is present...this you can only check by testing several stainings with similar results for standard compound AND compound in sample
Especuially in pharmaceutical literature, a lots of helpful studies about flavonoid-TLC analysis are described...
read this paper
https://www.researchgate.net/publication/308586568_Phytochemical_Evaluation_of_Polyherbal_Formulation_of_Clinacanthus_nutans_and_Elephantopus_scaber_to_Identify_Flavonoids
Article Phytochemical Evaluation of Polyherbal Formulation of Clinac...
Hi,
You need to use standards, and perform the TLC with your sample and standards, at the same time. You then compare the retardation ration of each spot to identify which is related to your sample.
I used a ferric chloride sprayed-TLC plate to detect the presence of phenolic compound in your fermentation medium. The instant formation of pink to orange-brown colored spot of the aliquot indicated the presence of phenolic compound in the medium
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