Kinetic Spectrophotometric Method for 4-nitrophenol Determination in Drinking Water

Resumo

This paper describes a rapid, highly sensitive and simple kinetic spectrophotometric method for determination of p-nitrophenol (p-NP) based on its activating effect on sulfanilic acid oxidation by hydrogen peroxide in basic media in the presence of Co²⁺ as catalyst. Coloration of sulfanilic acid is used to monitor the reaction spectrophotometrically at 368 nm. p-Nitrophenol can be determined in the ranges of 40‒200 and 200‒400 ng/mL under optimal conditions. The detection limit of the method according to 3σ criteria is 8 ng/mL. The RSD is 4.8‒0.8% for concentration interval 40‒200 ng/mL. The kinetic parameters of the reaction are reported, and the rate equations are suggested. The developed procedure was successfully applied to the rapid determination of p-NP in water samples using solid phase extraction for phenol preconcentration and removing interferences. The HPLC method was used as comparative method to verify results.