Folin-Ciocalteu method

Abstract In this study, a new natural adsorbent (sumae leaves) for removing Cu (II) ion from the aqueous solutions has been investigated. Leaves of sumae were obtained from Siirt, Tmkey. The tannins were extraeted with acetone water (70 30, v/v) mixture from the leaves of sumac. For the total tannin determination Folin-Ciocalteu method was used and tannin content was found 27%. In batch experiments, pH profile, adsorption time, adsorbent/hquid ratio, initial concentration of metal ions, adsorbent amoimt, particle size of adsorbent and temperature were performed to determine binding properties of adsorbent for the Cu(II) ions. The concentrations of the metal ions in solutions before and after adsorption were measured with an atomic absorption spectrophotometer. 

A calibration graph 3-15 ppm TA concentration range was constructed and the content of tannins in sumac leaves was determined by the Folin-Ciocalteu method. 

Leaves of Sumac were used for removal of ions in aqueous solution. Tannins were extracted from the leaves of sumac by extracting with 70% (v/v) acetone-water solution. For the total tarmin determination Folin-Ciocalteu method was used and tannin content was found 27%. Various adsorption parameters for the effective removal of Cu + ions by using sumac leaves as an adsorbent from aqueous solutions were studied and optimized. 

The Falin-Ciocalteu reagent (FCR) is a complex formed in a reaction between sodium tungstate and sodium molybdenate in hydrochloric add and phosphoric acid, which turns yellow after lithium sulphate is added. The reagent reads in an alkaline environment with reducing compounds. Such a reaction gives a blue chromophore which is observed by colorimetry. The Folin-Ciocalteu method is highly sensitive - both to phenolic and non-phenolic compounds, e.g. proteins, vitamin C, vitamin Bj, folic acid, Cu(I). The method is applied most frequently to determine the total content of phenolic compounds [34,35]. If that is the case, a sample for determination should be prepared in a proper manner to minimise the effect of non-phenolic... 

A third method relies on the precipitation of proanthocyanidins with formaldehyde. First, the total phenolic content is measured using the Folin-Ciocalteu reagent as described before. A 0.5 mole equivalent of phloroglucinol (1.3) is added for every gallic acid equivalent in the extract. To 2 mL of this plant extract and phloroglucinol is added 1 mL of a 2 5 HC1 /H20 solution and 1 mL of an aqueous solution of formaldehyde (13 mL of 37% formaldehyde diluted to 100 mL in water). After an overnight incubation at room temperature, the unprecipitated phenols are estimated in the supematent by the Folin-Ciocalteu method. The precipitate contains the proanthocyanidins and the known amount of phloroglucinol, which is always quantitatively precipitated. 

Abstract. Adsorption of antioxidants (vitamins C and E) from aqueous and ethanol solutions on unmodified and partially hydrophobized nanosilica A-200 was studied using UV spectroscopy and quantum chemical methods with consideration for the solvent effects. Antioxidant power of silica nanocomposites with immobilized vitamins was evaluated by measuring the total polyphenolic index following the Folin-Ciocalteu method. It has been shown that immobilization of vitamins on silica surface leads to their stabilization. Being released from the carrier molecules of vitamins do not lose their antioxidant properties... 

As can be seen from the data, after 30 min of reaction maximum antioxidant power is observed for unmodified silica, with the index being approximately twice as much compared to the control solution. Modified silica also shows an increase in antioxidant power by 30-35% compared to the control solution. The data are in agreement with previous results showing the stabilization of vitamin C on the silica surface, and its slower desorption from the surface of modified samples. Unfortunately, it is not possible to determine the antioxidant activity of vitamin E by the Folin-Ciocalteu method since it is insoluble in aqueous solution. 

Today, the most widely used method for the estimation of total phenolics in plant extracts as well as in foods and beverages is the Folin-Ciocalteu method. Some authors prefer the Prussian blue method, because... 

Folin- Ciocalteu method See Folin-Denis. see Folin-Denis reagent commercially available alterations longer heating, addition of HCI and U2SO4 effects compared to Folin-Denis method no precipitates. absorption band is sharper and more symmetrical, more sensitive, slightly less color with other reductants 47,49,110, Ml... 

For synthesized Gelatin (G)/Tannin (T) resins, gelatin powder was purchased from tilker Food Company-Istanbul, Turkey. Flydrolyzable tannins were obtained from the sumac leaves which were collected from Siirt, Turkey. The raw leaves were dried at room temperature in dark and then ground 500 pm particle sizes. For the total tannin determination Folin-Ciocalteu method was used and tannin content found 27%. Tannins are extracted from sumac leaves with 1 1 (v/v) acetone/water solution [15]. Tannic acid (TA) powder, which was extracted from sumac leaves (30 g) was dissolved in distilled waster at 95-98°C, then solution cooled at room temperature and 37% formaldehyde solution added to the solution. G powder was dissolved distilled water at 95-98°C and then added to the TA/formaldehyde solution. Concentrated hydrochloric acid was added to the mixture and heated 95-98°C for 12 h with a reflux condenser. G/TA resin was washed distilled water, dried at 110°C. Dried resin was crushed into small particles, <500 pm [16]. 

Colorimetric Indirect Method based on the typical reaction of polyphenols with formaldehyde, Singleton " proposed an assay for the quantification of phenolic material condensable with formaldehyde. He described a colorimetric procedure, instead of the gravimetric method, combining the Folin-Ciocalteu assay wifii the method of Stiasny (Fig 2). First, the total phenol content of the extract was measured before the precipitation reaction by the Folin-Ciocalteu method following the... 

Table 2. Total phenols content in each extract by the Folin-Ciocalteu method.

The same sample was then analyzed for protein by the modified Folin-Ciocalteu method." A correction was made for the color of the antigen. To test the method ten triplicate analyses were run on purified antibody samples by both the modified Folin-Ciiocalteu and the Nessler method by two analysts. The first method gave values which averaged 1.035 0.035 times the second. 

The Folin-Ciocalteu method, which is also an antioxidant capacity assay based on the use of molybdotungstophosphate heteropolyanion reagent, has been also modified to enable the simultaneous determination of hydrophilic and lipophilic antioxidants, such as PG and DG [84]. The modification was performed by using an isobutanol-diluted version of the reagent and providing an alkaline medium with aqueous sodium hydroxide such that both organic and aqueous phases, necessary for lipophilic and hydrophilic antioxidants, respectively, were supplied simultaneously. 

Attard, E. 2013. A rapid microtitre plate Folin-Ciocalteu method for the assessment of polyphenols. Central Eur. J. Biol. 8(l) 48-53. 

Rover, M. R. Brown, R. C., (2013). Quantification of total phenols in bio-oil using the Folin-Ciocalteu method. J. Anal. Appl. Pyrol, 104, 366-371. J ANAL APPL PYROL Sajilata, M. G., Singhal, R. S. Kamat, M. Y. (2008). The Carotenoid Pigment Zeaxanthin -... 

Virgin coconut oil is a important source of phenolic compounds. Total phenolic contents of the virgin coconut oil are quantified by means of Folin-Ciocalteu method. For detection a quantification of of phenolic compoimds several methods have been described. The most used technique has been HPLC, coupled to florescenee detection (Seneviratne Sudarshana Dissanayake 2008), diode array detector (Seneviratne et al., 2009), or UV-Vis detector (Santos et al., 2013). 

---