Total phenolic content the Folin-Ciocalteu reagent

1 Total phenolic content the Folin-Ciocalteu reagent 

Dilute an aliquot of the sample 10 1 with water (9 parts water to 1 part sample). This is not necessary if the phenol content is low. 

Add 2 ml of freshly prepared 2% (w/v) sodium carbonate (anhydrous) to 0.1 ml of the sample extract (diluted if necessary). 

Allow the sample to stand for a minimum of 30 minutes, but not more than one hour. 

For blanks one can use ethanol, water or methanol, whichever the tissue extract was dissolved in last. Since this is a spectrophotometric assay, it is important to have a standard curve to relate the absorbance value to a concentration. Common compounds used to generate a standard curve are chlorogenic acid (1.18) or gallic acid (1.5). The concentration of phenolic compounds is then reported as chlorogenic acid or gallic acid equivalents, respectively. 

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