scholarly journals Voltammetric determination of polyphenolic content in pomegranate juice using a poly(gallic acid)/multiwalled carbon nanotube modified electrode

2016 ◽  
Vol 7 ◽  
pp. 1104-1112 ◽  
Author(s):  
Refat Abdel-Hamid ◽  
Emad F Newair
Keyword(s):  
Carbon Nanotube ◽  
Gallic Acid ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Direct Determination ◽  
Multiwalled Carbon Nanotube ◽  
Pomegranate Juice ◽  
Total Phenolic ◽  
Multiwalled Carbon

A simple and sensitive poly(gallic acid)/multiwalled carbon nanotube modified glassy carbon electrode (PGA/MWCNT/GCE) electrochemical sensor was prepared for direct determination of the total phenolic content (TPC) as gallic acid equivalent. The GCE working electrode was electrochemically modified and characterized using scanning electron microscope (SEM), cyclic voltammetry (CV), chronoamperometry and chronocoulometry. It was found that gallic acid (GA) exhibits a superior electrochemical response on the PGA/MWCNT/GCE sensor in comparison with bare GCE. The results reveal that a PGA/MWCNT/GCE sensor can remarkably enhance the electro-oxidation signal of GA as well as shift the peak potentials towards less positive potential values. The dependence of peak current on accumulation potential, accumulation time and pH were investigated by square-wave voltammetry (SWV) to optimize the experimental conditions for the determination of GA. Using the optimized conditions, the sensor responded linearly to a GA concentration throughout the range of 4.97 × 10−6 to 3.38 × 10−5 M with a detection limit of 3.22 × 10−6 M (S/N = 3). The fabricated sensor shows good selectivity, stability, repeatability and (101%) recovery. The sensor was successfully utilized for the determination of total phenolic content in fresh pomegranate juice without interference of ascorbic acid, fructose, potassium nitrate and barbituric acid. The obtained data were compared with the standard Folin–Ciocalteu spectrophotometric results.

Photoacoustic Approach to Direct Determination of the Total Phenolic Content in Red Sorghum Flours

2004 ◽  
Vol 52 (8) ◽  
pp. 2133-2136 ◽  
Author(s):  
Otto Dóka ◽  
Dane D. Bicanic ◽  
Mamoudou H. Dicko ◽  
Maja A. Slingerland
Keyword(s):  
Total Phenolic Content ◽  
Phenolic Content ◽  
Direct Determination ◽  
Total Phenolic

scholarly journals PENETAPAN KADAR FENOLIK TOTAL FRAKSI POLR DAN NONPOLAR DAUN RAMBAI LAUT (Sonneratia caseolaris L.) DENGAN METODE SPEKTROFOTOMETRI UV-Vis

2019 ◽  
Vol 1 (2) ◽  
pp. 140-147
Author(s):  
Siti Jubaidah ◽  
Reksi Sundu ◽  
Nur Sabriningsih
Keyword(s):  
Gallic Acid ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Ethanol Extract ◽  
Polar Fraction ◽  
Total Phenolic ◽  
Mangrove Forests ◽  
Sonneratia Caseolaris ◽  
Nonpolar Fraction

Rambai laut (Soneratia caseolaris L.) is a type of tree that grows in riverbank swamps or mangrove forests which contains one of the secondary metabolites in the form of phenolic compounds. The purpose of this study was to determine the total phenolic content of polar and nonpolar fractions of sea rambai leaves using UV-Vis spectrophotometry method. Research conducted is non-experimental. The stages of the study included the determination of plants, sampling, making samples, making extracts, determining the water content of extracts, fractionation using polar and nonpolar fractions, phytochemical screening test of ethanol extract and fractionation results and determination of total phenolic levels by UV-Vis spectrophotometry. The results showed that rambai laut leaf in polar fraction had a total phenolic content of 213.49 ± 1.2227 mg GAE / g, which means that in each gram the polar fraction is equivalent to 213.49 mg of gallic acid, whereas in the nonpolar fraction of rambai laut leaves is obtained 55.79 ± 1.0809 mg GAE / g which means that in each gram the nonpolar fraction is equivalent to 55.79 mg of gallic acid. Total phenolic content is greater in the polar fraction.

scholarly journals Determination of Total Phenolic Levels in Ethanol Extract of Moringa (Moringa oleifera L.) Leaves based on Differences in Growing Sites

2021 ◽  
pp. 403-411
Author(s):  
Any Guntarti ◽  
Nining Sugihartini ◽  
Siti Athiyah Umaiyah ◽  
Nina Salamah
Keyword(s):  
Phenolic Compounds ◽  
Gallic Acid ◽  
Total Phenolic Content ◽  
Moringa Oleifera ◽  
Phenolic Content ◽  
Ethanol Extract ◽  
Total Phenolic ◽  
Nutritional Content ◽  
Method Analysis

Moringa oleifera L. have good nutritional content including phenolic compounds which can be used as antioxidants and can grow in lowlands and highlands. The purpose of this study was to determine the total phenolic content of the ethanol extract of M. oleifera leaves with variations in the area of ​​collection. The 50% ethanol extract was obtained from the simplicia of M. oleifera leaves by using the maceration method. Analysis of total phenolic content in the extract was carried out using a spectrophotometer instrument with the addition of reagent Folin-Ciocalteu and gallic acid as standard. The results of total phenolic content in Sleman, Wonosari, and Wonosobo areas were (127.87 ± 2.71) mg GAE / g extract, (99.40 ± 2.68) mg GAE / g extract, and (142 , 92 ± 1.81) mg GAE / g extract. The highest phenolic content in the ethanol extract of moringa leaves was found in Wonosobo areas.

Determination of Total Phenolic Content Using the Folin-C Assay: Single-Laboratory Validation, First Action 2017.13

2018 ◽  
Vol 101 (5) ◽  
pp. 1466-1472 ◽  
Author(s):  
Steve Kupina ◽  
Chris Fields ◽  
Mark C Roman ◽  
Sharon L Brunelle
Keyword(s):  
Gallic Acid ◽  
Dietary Supplement ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Collaborative Study ◽  
Total Phenolic ◽  
Skin Extract ◽  
Method Performance ◽  
Single Laboratory

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. The method is composed of a water extraction of dried extracts with sonication followed by reaction with the Folin-C reagent. The resulting colorimetric reaction is measured at 765 nm and compared with a standard curve generated with gallic acid standard solutions. The validation results were compared with Standard Method Performance Requirement (SMPR®) 2015.009, developed by the Stakeholder Panel on Dietary Supplements. The method demonstrated acceptable within-day RSDr of 1.96–7.47% for the five matrixes studied (grape seed extract, grape skin extract, black tea extract, green coffee extract, and cocoa extract). When gallic acid was spiked into maltodextrin (a surrogate dietary supplement carrier) at 30 or 70%, the recovery ranged from 91 to 104%, within the acceptable range established by SMPR 2015.009. Selectivity testing with glucose, fructose, and sucrose demonstrated no positive interference by these compounds. Finally, ruggedness studies demonstrated no significant effects due to changes in the heating apparatus, test material weight, read time after reaction, amount of Folin-C reagent, reaction time, reaction temperature, and amount of Na2CO3. The single-laboratory validation results support adoption of the method as First Action Official MethodSM 2017.13 and further evaluation in a collaborative study.

scholarly journals Determination of the Total Phenolic Content in Wine Samples Using Potentiometric Method Based on Permanganate Ion as an Indicator

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3279
Author(s):  
Ziqi Sun ◽  
Yufeng Zhang ◽  
Xinyue Xu ◽  
Minglin Wang ◽  
Lijuan Kou
Keyword(s):  
Gallic Acid ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Rapid Determination ◽  
Accurate Determination ◽  
Potentiometric Sensor ◽  
Total Phenolic ◽  
Linear Potential ◽  
Permanganate Ion

A rapid and accurate determination method for total phenolic content is of great importance for controlling the quality of wine samples. A promising potentiometric detection approach, based on permanganate ion fluxes across ion-selective electrode membranes, is fabricated for measuring the total phenolic content of wine. The results show that the presence of phenols, such as gallic acid, leads to a potential increase for the potentiometric sensor. Additionally, the present sensor exhibits a linear potential response with the concentration range from 0.05 to 3.0 g/L with a detection limit of 6.6 mg/L calculated using gallic acid. These sensors also exhibit a fast response time, an acceptable reproducibility and long-term stability. These results indicate that the proposed potentiometric sensor can be a promising and reliable tool for the rapid determination of total phenolic content in wine samples.

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