Spectrophotometric determination of some phenolic compounds using N, N- diethyl –p-phenylenediamine (DE-PPD)‎ and benzoyl peroxide

الملخص EN

A rapid and sensitive spectrophotometric method has been developed for the determination of some phenolic compounds (phenol, oaminophenol and α-naphthol) and was applied for determination of amoxicillin drug.

The method is based on oxidative coupling reaction of these compounds with N,N-diethyl-p-phenylenediamine in the presence of benzoyl peroxide as oxidizing agent.

The formed blue indophenol dyes have maximum absorptions at 627, 612.5, 611.5 and 628.5 nm.

for phenol, o-aminophenol, α-naphthol and amoxicillin respectively.

The molar absorptivities are 1.72× 104, 1.92× 104, 1.65 × 104.

l.

mol-١.

cm-1 for concentrations obeyed Beer,s law in the ranges 0.2 -4.0, 0.5 -11.0, 0.6 – 16.0 and 0.8 – 25.0 μg ml-1 for the above compounds respectively.

The average recovery % was ranged between 98.99% 100.45 with relative standard deviation ≤ 1.04 for all the studied compounds.

The method is applied successfully to the assay of amoxicillin.