Enhancement of surfactants in the electrochemical determination of phenols and the mechanisms research

The electrochemical responses of phenols can be enhanced effectively by using surfactants at the glassy carbon electrode. The enhancement of surfactant, including cetyl trimethyl ammonium bromide and cetyl pyridinium chloride, on trinitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, o-dihydroxy-benzene, p-dihydroxy-benzene, 1-naphthol, 2-naphthol and triphenol has been investigated in HAc–NaAc buffer solution, and most of the results are reported first. The interaction mechanism among the electrode, surfactant and detected phenols was studied comprehensively and two mechanism models were suggested. One is electrostatic effect model and the other is hydrogen bond model. The optimal conditions, such as pH value, concentration of surfactant used, were also studied in detail. For ionized phenols, the optimal concentration of surfactant added was 1.0 × 10−4 mol L−1, which was well below the critical micelle concentration. For nonionized phenols, the respective value was 1.2 × 10−3 mol L−1, which was close to the critical micelle concentration. All of the results obtained will be of great significance to the determination of phenols and substituted phenols.