Determination Of Phenols In Water Research Articles

A Plot of the pH vs. the Logarithm of the Titrant Volume in Potentiometric Titration. The Determination of Phenol in Water

Abstract The determination of phenol in water was successfully carried out by means of a new plot of the potentiometric titration data. The plot of the pH vs. the logarithm of the titrant volume gave a titration curve with an inflection between two linear portions, and the center of the inflection obtained by a graphical method was found to correspond to the equivalence point. In the titration of phenol, the data fitted well to the theoretical curve by taking into account the hydrolysis of the phenol ion. The mean of the results obtained from the apparent equivalence point in the concentration range of 1.0–7.7×10−3 mol dm−3 was 101.2% of the results obtained iodometrically after the bromination of phenol, and the precision of the results was ±2.7% (S.D.).

Fluorometric determination of phenols in water

A fluorophotometric determination of phenols in waste water was developed. Sample water was distilled and the total phenols in the distillate was measured spectrofluorophotometrically at exitation, 278nm, and emission, 299nm. Various inorganic salts did not interfere, but some organic compounds, such as formaldehyde and aniline, interfered with the determination. This method was compared with an official 4-aminoantipyrine method. The good agreements were obtained. This method is useful for the research of environmental pollution because of it's accuracy and easiness.

Chromatographic determination of phenols in water.

Chromatographic determination of phenols in water.

An evaluation of the 3-methyl-2-benzothiazolinone hydrazone method for the determination of phenols in water and waste waters.

Friestad's method for the determination of phenol with 3-methyl-2-benzo-thiazolinone hydrazone (MBTH) has been evaluated. The Friestad manual and automated MBTH methods were modified to lower the detection limit from 1 mg l–1 to 1 µg l–1. The values for phenol obtained by this method on river water and industrial waste samples were equal to or greater than those obtained by the 4-aminophenazone method.

An Improved Method for the Isolation of Phenols from Water

Abstract A rapid and sensitive method for the separation and isolation of phenols from waters is described. A column adsorption and desorption procedure is used prior to the analysis by colorimetry with aminoantipyrine. The determination of phenols in water may be accomplished by many different analytical methods. At mg/l levels and higher, ultraviolet absorption spectrophotometry is often used for analysis in waste and effluent waters1,2. Phenols are determined at ug/l by colorimetry using the aminoantipyrine method3. In this procedure the phenols are separated from non-volatile impurities by a distillation at pH 4. The aqueous phenolic solution is adjusted to the proper pH and reacted with 4-aminoantipyrine in the presence of potassium ferricyanide to produce a colored dye which is concentrated by extraction into chloroform. The absorbance of the chloroform solution is then measured. The distillation procedure for the separation of the phenols is quite time-consuming requiring a few hours for completion...

Factors influencing the condensation of 4-aminoantipyrine with derivatives of hydroxybenzene—II. Influence of hydronium ion concentration on absorptivity

The oxidative coupling of 4-aminoantipyrine with several hydroxy derivatives of benzene has been examined at pH values of 8.0 and 10.0. A reaction mechanism has been proposed. It appears that 4-aminoantipyrine exerts an electrophilic attack upon the para position of the phenol. [H 3 +O] influences this attack in two ways: (a) greater reactivity is observed at pH 8.0 as the phenol exhibits greater dissociation to a phenoxide ion. This is ascribed to more favorable reaction kinetics offered by the stronger electron-releasing properties of the −0 −, and (b) lesser reactivity is observed at pH 10.0 that is ascribed to a reduction of the electrophilic characteristics of the 4-aminoantipyrine. Substitution in the para position of the benzene ring influences the reaction in two ways: (a) oxidative coupling is blocked apparently by such substituents as CH 3-, C 2H 5-, C 6H 5-, and (b) oxidative coupling is altered by such substituents as Cl-, Br-, NH 2-, CH 3-, and C 2H 5O-. The latter may be due to electrophilic displacement and migration of the substituent or to formation of azo-type structures. The data offered herein very strongly shows the limitations of the analytical application of 4-aminoantipyrine for determination of phenols in water and waste water. Some advantage may be gained by conducting the reaction at a pH value of 8.0 where kinetics are more favorable.

Factors influencing the condensation of 4-aminoantipyrine with derivatives of hydroxybenzene—I. A critique

The quantitative determination of phenols in water and waste water is attempted by condensation with 4-aminoantipyrine and oxidation under alkaline conditions to a colored product. The major chemical factors that influence this reaction are pH value between 8.0 and 11.0, the type of aqueous buffer, and the type of substituted phenol. These three factors influence the analytical and molecular sensitivities as well as the wave length of maximum absorbance. A “total phenol” determination is not possible with the 4-aminoantipyrine technique as currently practiced.