i am trying to extract phenolics compounds (folin ciocalteu method) but there two things that i didn"t understund in the protocol. First the quantity of this reagent ( folin ciocalteu ) to add ? and second , calibration of the spectro ,using gallic acid . why gallic acid and how to do this calibration . thanks for all you answer.
Hello Maher,
As I know, you can not use this method for the exaction of phenolics. in our lab we are using this method to evaluate the amount of phenolic compounds in various samples (plant or berries extracts). What sample are you working with?
Here you have the protocol that we are using:
Aliquots of 25 μl sample were mixed with 1.8 ml distilled water in a 24 wells microplate. An aliquot of 120 μl of Folin-Ciocalteu reagent was added and mixed,
followed, after 5 minutes by addition of 340 μl Na2CO (7.5% in water) in order to create basic conditions (pH ~10) for the redox reaction between phenolic compounds and FolinCiocalteu reagent. After incubation for 90 min at room temperature, the absorbance was read at 750 nm by microplate reader (BioTek Instruments, Winooski, VT), against the blank, in which the standard or sample were replaced with methanol. Sample dilution was done when the recorded absorbance value exceeded the linear range of the gallic acid curve.
Standard curve was performed using concentrations of 0, 0.25, 0.50, 0.75, 1 mg/ml
of gallic acid. Total phenolic content is expressed as gallic acid equivalents, mg of GAE/ 100 g FW.
If you have any question please let me know!
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thank you zorita for your useful response . but why you said that we can not use this method ? AND HOW much FolinCiocalteu reagent we put for each exemple ? regards !
Here you are the description of this reagent and its uses.
https://en.wikipedia.org/wiki/Folin%E2%80%93Ciocalteu_reagent
Folin-Ciocalteu is a method to measure the concentration of polyphenols not to extract them.
Actually the Folin-Ciocalteu reagent reacts with REDUCING SUBSTANCES, it is very misleading that it is labelled as "Total polyphenols", for example there is interference from ascorbic acid, proteins etc.
Agreed with the views of previous commentors. Would like to share some useful literature on the topic. It may explain your queries. Hope it helps.
For extracting polyphenols, you can use several types of sovent. water, ethanol, methanol, n-hexane,... and following steps are dry you materials, grin, soak them into the solvent and then concentrated the solution.
With this method it is possible to only detect colorimetrically the phenolic compounds. To promote degradation you would have to use some other kind of method such as bioremediation with polyphenoloxicity or an advanced oxidative method, I suggest photodegradation with the use of titanium oxide as a catalyst, exposing to UV light.
Hello, the folin-ciocalteau method is suitable for detecting phenolic compounds in samples and various sources. Gallic acid is the standard compound used to assemble the analytical reference curve. Therefore, it is ideal that you build an analytical curve (I suggest using Origin Pro Software to assemble the analytical curve) with different concentrations of gallic acid. By assembling the curve and regressing you will get the equation of the straight line for and by getting the absorbance values of the analyzes of your substance of interest, just throw in the equation of the straight line obtained from the standard curve (gallic acid) and you will have the concentration values of phenolic compound from your sample. This manuscript may answer some of your questions:
Application and Analysis of the Folin Ciocalteu Method for
the Determination of the Total Phenolic Content from
Limonium Brasiliense L.
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