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Aminoantipyrine-ferricyanide reagent

Comment now is to be centered on the AutoAnalyzer total alkaline phosphatase method, using phenyl phosphate as substrate and the Powell and Smith aminoantipyrine-ferricyanide reagents, formulated in Fig. 3. [Pg.265]

The total phenolic compounds in an aqueous sample can be determined by a colorimetric method using 4-aminoantipyrine. This reagent reacts with phenolic compounds at pH 8 in the presence of potassium ferricyanide to form a colored antipyrine dye, the absorbance of which is measured at 500 nm. The antipyrine dye may also be extracted from the aqueous solution by chloroform. The absorbance of the chloroform extract is measured at 460 nm. The sample may be distilled before analysis for the removal of interfering nonvolatile compounds. The above colorimetric method determines only ortho- and meta-substituted phenols and not all phenols. When the pH is properly adjusted, certain para-substituted phenols, which include methoxyl-, halogen-, carboxyl-, and sulfonic acid substituents, may be analyzed too. [Pg.223]

The reaction takes place best in the pH range from 7.5 to 9.5, regardless of the type of buffer used, but it must have a sufficient capacity to prevent a drop in pH during the reaction. For the reaction it is further important that the ratio of reagents be close to that of one mole of aminoantipyrine to one oxidation equivalent of the oxidant, and then a ten to fiftyfold excess of the reagent (phenol as the base of calculation) also be secured. Potassium ferricyanide or alkaline persulfate may be used as oxidants. The former is preferable because of its greater stability in aqueous solution (11). [Pg.194]

Reagent 1% aqueous solution of 4-aminoantipyrine, borate buffer of pH 9-9.5 or a 5% NaHCOa solution, 3% potassium ferricyanide or 1% persulfate solution. [Pg.194]


See other pages where Aminoantipyrine-ferricyanide reagent is mentioned: [Pg.352]    [Pg.331]   


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