Abstract
In this paper, a simple, convenient and sensitive electrochemical method has been developed for the determination of C.I. Direct Red 80. A gold nanoparticle modified carbon paste electrode was fabricated and used for study and sensitive determination of Direct Red 80 by cyclic voltammetry and differential pulse voltammetry. The overall analysis involved a two-step procedure: an accumulation step under open-circuit conditions, followed by voltammetric measurements of Direct Red 80 in a 0.1 M phosphate buffer solution at pH = 3.0. The experimental conditions, such as the medium, pH and accumulation time, were optimised. The oxidation peak current was proportional to the concentration of Direct Red 80 from 5.0 × 10−8 to 5.0 × 10−7 M and 5.0 × 10−7 to 3.0 × 10−6 M, and the detection limit was 1.15 × 10−8 M (S/N = 3). The proposed method was used to detect Direct Red 80 in natural water and sewage with good accuracy.
Acknowledgements
The authors express their appreciation to the University of Kashan research councils for their financial support of this work.