Determination of morphine at gold nanoparticles/Nafion® carbon paste modified sensor electrode

Abstract

A novel and effective electrochemical sensor for the determination of morphine (MO) in 0.04 mol L⁻¹ universal buffer solution (pH 7.4) is introduced using gold nanoparticles electrodeposited on a Nafion modified carbon paste electrode. The effect of various experimental parameters including pH, scan rate and accumulation time on the voltammetric response of MO was investigated. At the optimum conditions, the concentration of MO was determined using differential pulse voltammetry (DPV) in a linear range of 2.0 × 10⁻⁷ to 2.6 × 10⁻⁴ mol L⁻¹ with a correlation coefficient of 0.999, and a detection limit of 13.3 × 10⁻¹⁰ mol L⁻¹, respectively. The effect of common interferences on the current response of morphine namely ascorbic acid (AA) and uric acid (UA) is studied. The modified electrode can be used for the determination of MO spiked into urine samples, and excellent recovery results were obtained.