Enhanced Effects of Surfactant on Sensing of Phenol on a Graphene Nano-sheet Paste Electrode

This article presents an enhanced sensitivity for the determination of phenol using a graphene nano-sheet paste (GNP) electrode in the presence of sodium dodecyl sulfate (SDS). The concentration of SDS, pH and other factors were examined. In pH 8.70 phosphorate buffer solution, the oxidation peak of phenol was observed at 0.67 V vs SCE on the GNP electrode. The relationship between peak currents and phenol concentrations is linear in the range of 8.0×10-8 ～ 8.0×10-5 mol/L, with ip (μA) = 0.27888 + 0.04975C (μmol/L), R = 0.99926 (n = 9) and the detection limit for phenol is 5.0×10-8 mol/L. The electron transfer coefficiency β was evaluated to be 0.592, the standard rate constant k0 was estimated to be 2.77×10-4 cm/s. The diffusion coefficiency for phenol was found to be 5.45×10-4 cm 2 /s. This electrode has excellent reproducibility and stability in the determination of phenol in soil samples, thus, this method is expected to apply in determining the concentration of phenol in soil. A hemimicelle model was suggested to explain the enhanced current for the oxidation of phenol