Folin-Ciocalteu

Fluorescence stabilization, porphyrins la 100-101 Fluorophors la 57 Flupentixol lb 354 Fluphenazine la 104 lb 354-356 Fluspirilen lb 354 Fluvalinates lb 86 Foam bath, brominated la 64 Folic acid la 223,225 Folin-Ciocalteu s reagent lb 180 Folin s reagent lb 321 Formaldehyde la 299,351 -, vapor la 86 Formazan lb 65... 

SINGLETON v L, ORTHOFER R and LAMUELA-RAVENTOS R M (1999) Analysis of total phenolics and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent, Meth Enzymol, 299, 152-78. 

Singleton, V. L., Orthofer, R., and Lamuela-Raventos, R. M. (1999). Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. In "Methods in Enzymology, Oxidant and Antioxidants (Part A)", (L. Packer, Ed.), vol. 299 pp. 152-178. Academic Press, San Diego, CA. 

Materials required Sample solution in methanol, distilled water, 20% Na2C03, Folin-Ciocalteu s phenol reagent, water bath, graduated tube, cuvette, micro pipette (0.1 ml), pipette of 1,2 and 10 ml, test tubes of 20 ml, pure ferulic acid (Serva, Germany), Shimadzu UV 160 spectrophotometer. 

Procedure A 0.002 ml aliquot of the sample solution in methanol was taken and 7 ml distilled water plus 0.1 ml Folin-Ciocalteu s phenol reagent was added and after 3 min 0.2 ml of 20% Na2C03 was included. After boiling at 90 °C (exactly 5 min) samples were cooled at room temperature and were diluted with HzO to 10 ml volume. Only distilled water and reagents were used as a blank. The absorbance of total phenolics was measured at 660 nm spectrophotometrically (a Shimadzu UV 160 spectrophotometer) as per Feldman and Hanks (1968), with a sensitivity of 0.05 pig/g d.w. A standard curve was constructed with different concentrations of ferulic acid (Serva, Germany). Concentrations of ferulic acid varied from 0.33-80jig/ml (Table 1). 

The Folin-Ciocalteu assay is the most widely used method to determine the total content of food phenolics (Fleck and others 2008). Folin-Ciocalteu reagent is not specific and detects all phenolic groups found in extracts, including those found in extractable proteins. A disadvantage of this assay is the interference of reducing substances, such as ascorbic acid (Singleton and others 1999). The content of phenolics is expressed as gallic acid or catechin equivalents. 

Total Phenols Assay (Folin-Ciocalteu Reagent)... 

Magalhaes LM, Segundo MA, Reis S, Lima JLFC and Rangel AOSS. 2006. Automatic method for the determination of Folin-Ciocalteu reducing capacity in food products. J Agric Food Chem 54(15) 5241-5246. 

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. 

Determination of TA in Sumac Sample Solutions by Folin-Ciocalteu (FC) Method... 

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. 

Methods used for the detection of PAs in cmde or partially purified extracts can also be adapted for post-column analysis after fractionation (see below). Direct quantitative analysis of PAs in crude grape phenolic extracts is often impossible due to the complex sample matrix. Thus, fractionation or purification is often necessary before analysis. The Folin-Ciocalteu and Pmssian Blue assays are widely used for the quantification of total polyphenols in plants [27,28]. These methods are not specific for PAs due to the reaction of other phenolic compounds with these reagents. 

A detailed discussion of Folin-Ciocalteu s phenol protein determination method, especially with respect to possible disturbances and troubles and in comparison with the Bradford method, is given by Peterson (1996) loc. cit. 

G Mix just before use Soln. C, D, E, and F in a ratio of 1 1 28 10 H Folin-Ciocalteu s phenol reagent (stock), diluted 1+3 with ddH20... 

Clarke has reported that diloxanide furoate gives a blue color with the Folin-Ciocalteu Reagent, and also yields a yellow color when subjected to Libermann s test [7],... 

Diloxanide furoate was determined by Sane al. using a simple spectrophotometric method [28]. The drug was extracted from tablets with ethanol, or was filtered from a suspension and dissolved in ethanol. The resulting solution was mixed with 6% aqueous sodium hydroxide and Folin-Ciocalteu reagent, or with a 1% solution of sodium nitroprusside in aqueous 10% sodium hydroxide. The complexes formed had absorbance maxima at 650 run, or at 675 nm, respectively. 

Table 5.6 shows the total phenolic content (determined using the Folin-Ciocalteu assay) and antioxidant activity (ABTS radical scavenging capacity) of extracts from morama bean seed coat and cotyledon prepared with acidified mefhanol. If is clear fhaf morama bean seed coat and cotyledon have appreciable levels of fofal phenolics and antioxidant activity. These phenolics are concentrated in the seed coat. It has been reported that the morama bean cotyledon contains high levels of the amino acid tyrosine (Maruatona et ah, 2010) which is phenolic in nature and can therefore confribufe fo fhe fofal phenolic content of the cotyledon as determined with the Folin-Ciocalteu assay. 

In vitro tests, used in evaluation of antioxidant properties make use of the ability of antioxidants to quench free radicals. Based on this mechanism, the methods are divided into two groups SET - single electron transfer, and HAT - hydrogen atom transfer. Reactions with antioxidants in assays with the DPPH radical, ABTS and the Folin-Ciocalteu reagent both operate according to the SET and HAT mechanism. Due to the kinetics of the reaction, they are included in the... 

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... 

Performing the assay is reduced to putting an alcoholic solution of the analysed sample, Folin-Ciocalteu reagent and solution of sodium carbonate into a reaction tube, which brings the pH of the reaction environment to approx. 10. According to various literature reports, the reaction runs in the darkness for 10 to 120 minutes. After that time, the blue colour of the solution is observed colorimetrically at 725 nm - 760 nm [34, 35, 36, 37, 38]. The results are expressed based on calibration curves prepared for catechol and gallic acid. 

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