Spectrophotometric determination of paracetamol by reduction of 18-molybdo-2-phosphate heteropoly anion

Abstract EN

A very simple, rapid and sensitive spectrophotometric method for paracetamol assay in pharmaceuticals based on the reduction of 18-molybdo-2-phosphate heteropoly complex was developed.

Reaction of 18-molybdo-2-phosphate with paracetamol is very fast at room temperature.

The stoichiometry of the reaction is 1 : 1.

The molar absorptivity calculated for paracetamol was equal to that for heteropoly blue formed in the studied reaction and was of 1.15 X104 l mol-1 cm-1 at 820 nm.

Beer`s law was followed for paracetamol concentrations from 0.3 to 7.5 μg ml-1 (l = 1 cm).

The detection limit of the method was 0.03 μg ml-1 (l = 5 cm), and a relative standard deviation did not exceed 2.5 %.

The method was successfully applied to the determination of paracetamol in pharmaceuticals.