Estimation of Phenolic Compounds

Phenolic compounds which couple readily and completely with diazonium compounds can be estimated by titration with a standard diazonium solution. The standardisation of E salt affords one example of the method. 

Example.—/3-Naphthol.—1-44 gms. (TJ5 mol.) of /J-naphthol are dissolved in 10 c.cs. caustic soda solution (15%) to this is added 100 c.cs. water and 3 gms. of anhydrous sodium carbonate. The whole is then made up to 200 c.cs. in a flask. 50 c.cs. of this are placed in a beaker, and 

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The total concentration (C1 + C2) can be considered as a good estimation of global phenolic compounds concentration. According to the principle of the deconvolution method, the difference between the sample spectrum and the restituted one is defined by the quadratic error (see Chapter 3). If the quadratic error is higher than 5%, it means that other compounds are present and could interfere with the estimation of phenolic compound concentrations. In this case, no quantification is possible but a qualitative result can be displayed (presence of unknown compounds). 

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