University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Phenols, total

@ ChemSpider@ NIST@ PubChem

Citations 4

"Spectrophotometric Determination Of Total Phenolics By Solvent Extraction And Sorbent Extraction Optosensing Using Flow Injection Methodology"
Anal. Chim. Acta 1995 Volume 310, Issue 3 Pages 437-446
Wolfgang Frenzel* and Stephanie Krekler

Abstract: The method was based on the reaction of phenols with 4-aminoantipyrine (4-AAP). The reaction product was concentrated by (i) solvent extraction into CHCl3, or (ii) sorbent extraction using a C18-modified silica microcolumn. For i, sample was injected into a water carrier stream (2.8 ml/min) which merged with reagent streams (R1 and R2; 0.4 ml/min) containing 0.4 g/l 4-AAP of pH 10.2 and 0.1% potassium hexacyanoferrate(III) of pH 4, respectively, and was extracted with CHCl3 (0.6 ml/min). After passing though a phase separator the absorbance of the organic phase was measured at 460 nm. The calibration graph for phenol was linear for 0.02-0.5 mg/l, the detection limit was 8 µg/l and the RSD were 5%. For ii, a sample stream (2.6 ml/min) was merged with reagent streams R1 and R2 (0.6 ml/min; half the concentrations given above), passed through the microcolumn (3 cm x 2 mm i.d.) for 2 min and the imine product was eluted with methanol and detected at 460 nm. The calibration graph was linear for 0.02-500 mg/l phenol and the detection limit was 11 µg/l. Detection by oncolumn optosensing was also investigated using a Si microcolumn mounted in a light-emitting diode-based spectrophotometer with the first 3 mm of the sorbent illuminated (details given).
Spectrophotometry Sample preparation C18 Column Light emitting diode Optosensing Organic phase detection Preconcentration Silica Phase separator Solvent extraction

"Determination Of Total Phenols In Waters And Waste Waters Using Flow Injection With Electrochemical Detection; An Alternative To The Standard Colorimetric Procedure"
Anal. Chim. Acta 1996 Volume 323, Issue 1-3 Pages 39-46
M. J. Christophersen and T. J. Cardwell*

Abstract: The flow injection manifold for the determination of total phenols was equipped with an up-stream coulometric carbon electrode at +0.35 V (reference electrode not given) for the oxidative removal of interference followed by an amperometric carbon electrode at +0.78 V for the oxidative detection of phenols. Phosphate buffer of pH 6.8 was used as carrier (0.5 ml/min) and the injection volume was 10 µL. The method was calibrated with 2,5-dichlorophenol, and a linear calibration graph was obtained for 0.1-20 mg/l. RSD were 0.5-4% within the calibration range. The method was tested with several synthetic aqueous samples and found to give more accurate results for samples containing p-substituted phenols and nitrophenols than the 4-aminoantipyrine spectrophotometric method. The proposed method was applied to the analysis of industrial waste water samples.
Environmental Waste Amperometry Electrode Interferences

"Flow Injection Spectrophotometric Determination Of Total Phenols Using A Crude Extract Of Sweet Potato Root As Enzymic Source"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 111-118
Iolanda da Cruz Vieira and Orlando Fatibello-Filho*

Abstract: A flow injection spectrophotometric method is proposed for the determination of total phenols in industrial wastewaters. After selection of the extraction medium (e.g., buffer-to-tissue ratio, pH, buffer concentration, protective agents and/or stabilizers) and storage conditions, crude ext. of sweet potato root (Ipomoea batatas (L.) Lam.) was used as an enzymatic source of polyphenol oxidase (PPO; EC 1.14.18.1) directly in the carrier. This enzyme catalyzes the oxidation of mono-, di-, and polyhydric phenols to o-quinones which can couple to each other producing melanin-like pigments with a strong absorption at 410 nm. For the optimum extraction conditions, the enzyme activity did not vary for at least five months when stored at 4°C and decreased only 4-5% during an 8 h working period at 25°C. The results obtained for the determination of total phenols in industrial wastewaters are in good agreement with results obtained using a conventional manual method (correlation coefficient, r=0.9954). Twenty-six results were obtained per h, and the relative standard deviation (RSD) was less than 2.7% (n=6) for all samples. The detection limit (three times the signal blank/slope) was 1.0 x 10^-5 mol/L and the recovery of catechol from three samples ranged from 96.4 to 102.7% of added amt.
Industrial Spectrophotometry Optimization Enzyme Method comparison

"Peroxidase-Based Amperometric Sensor For The Determination Of Total Phenols Using Two-Stage Peroxidase Reactions"
Am. J. Enol. Vitic. 2001 Volume 52, Issue 4 Pages 381-385
Young-Tae Kong, Shin-ichiro Imabayashi, Kenji Kano, Tokuji Ikeda, and Takashi Kakiuchi

Abstract: A new method of measuring the total phenolic compounds in wine and tea is proposed. The method is based on the fact that the decreased amount of H2O2 caused by the action of peroxidase is proportional to the oxidized amount of phenolic compounds in the solution. Decrease in H2O2 was sensitively detected with a semipermeable-membrane-covered, horseradish-peroxidase-entrapped, and ferrocene-embedded carbon paste electrode. This electrode allows the detection of (+)-catechin down to 0.3 µM and the response is linear up to 15 µM. The content of total phenolic compounds in wine and tea samples determined by the present method agrees well with results obtained by the Folin-Ciocalteu method. Advantages of the proposed method over the Folin-Ciocalteu method include shorter detection time, smaller sample volume, one order of magnitude higher sensitivity, lesser degree of interference from coexisting SO2 and glucose, and applicability to colored, turbid, or colloidal samples. The method is not influenced by the oxygen level in samples. Samples require pretreatment if ascorbic acid is present.