The Folin-Ciocalteu (F-C) Assay was developed in 1927 for the measurement of tyrosine (1). The reagent consists of a mixture of sodium molybdate, sodium tungstate and other reagents. The assay has been used for many years by the food and agricultural industries for determining phenolic content of plant products (3).
What is Folin-Ciocalteu reagent?
The Folin–Ciocalteu reagent which is a mixture of tungstates and molybdates works on the mechanism of oxidation–reduction reaction. The method strongly relies on the reduction of the mixture heteropolyphosphotungsates–molybdates by the phenolic compound which results in the formation of blue coloured chromogen.
How do you use Folin-Ciocalteu reagent?
To perform an assay add x cm3 of sample (where x < 0.6) containing 5–100 μg of protein as required to (0.6– x) cm3 of water. Then add 3 cm3 of the alkaline copper solution. The solutions must then be mixed well and allowed to stand for 10 min at room temperature.
Why gallic acid is used as standard?
I found the details of Folin-Ciocalteu reaction, and the exact reason of choosing Gallic acid as a standard… the reasons are: Partly for historical reasons, In addition it is inexpensive, soluble in water, recrystallized easily from water, readily dried, and stable in the dry form.
How is total phenolic content measured?
The total phenolic content can be calculated as natural compound (gallic acid) equivalent (GAE) by the following equation: T= C XV/M .
Is Folin Ciocalteu reagent light sensitive?
Reagents are light-sensitive. In fact should be stored in dark glass bottles. phenols or phenolate anions reduce compounds of the Folin (complex of phosphomolibdic and phosphotungstic acids), which by transfer of electrons will pass from yellow to blue color.
What is the Folin Ciocalteu reagent and what is it used for?
Generally, Folin & Ciocalteu’s phenol reagent is used to determine protein concentrations between 1 to 100 μg/mL. However, the reagent exhibits a linear response to protein concentration up to 1000 μg/mL when used according to the instructions for kit Product No.
What happens in Folin Ciocalteu method?
The Folin-Ciocalteu method is described in several pharmacopoeias [12,13]. The reaction forms a blue chromophore constituted by a phosphotungstic- phosphomolybdenum complex [11,14], where the maximum absorption of the chromophores depends on the alkaline solution and the concentration of phenolic compounds [11].
How is gallic acid standard curve calculated?
Gallic acid is used as a standard compound and the total phenols were expressed as mg/g gallic acid equivalent using the standard curve equation: y = 0.0061x + 0.0396, R2 = 0.9991, Where y is absorbance at 760 nm and x is total phenolic content in the different extracts.
How is gallic acid standard prepared?
Preparation of standard Gallic acid solution Standard stock solution (primary) was prepared by dissolving 100 mg of gallic acid in 10 ml of 80% methanol and then making the volume to 100ml with distilled water in a 100 ml volumetric flask to get con- centration of 1mg/ml (1000µg/ml).
What is mg GAE g?
The total phenolic contents in all the samples were calculated by the using the formula: where C = total phenolic content mg GAE/g dry extract, c = concentration of gallic acid obtained from calibration curve in mg/mL, V = volume of extract in mL, and m = mass of extract in gram.
Which compound is used as standard for total phenolic content measurement?
gallic acid structure
Since gallic acid structure is one of the simplest phenolic molecule, it is usually the most common standard compound for total phenolics.
How does the Folin-Ciocalteu work?
The chemistry of the Folin-Ciocalteu is described and two Folin assays (single and dual reagent) are described for the assay of phenols and polyphenols with respect to experimental detail and critically evaluated for pure compounds and for mixtures (plant extracts). The single reagent method was found to be more precise and sensitive.
Can Folin & Ciocalteu’s phenol reagent be used to determine phenolic content?
Abstract A single-laboratory validation of a method using Folin & Ciocalteu’s phenol reagent (Folin-C reagent) for determination of total phenolic content of selected dietary supplement extracts was performed.
What does Folin-C stand for?
The method is composed of a water extraction of dried extracts with sonication followed by reac … A single-laboratory validation of a method using Folin & Ciocalteu’s phenol reagent (Folin-C reagent) for determination of total phenolic content of selected dietary supplement extracts was performed.
How do you mix gallic acid with Folin-Ciocalteu?
Left over gallic acid solutions can be poured down the drain. From each calibration solution, sample, or blank, pipet 20 µL into separate cuvettes, and to each add 1.58 mL water, and then add 100 µL of the Folin-Ciocalteu reagent, and mix well.
