The 2.5th order differential voltammetric determination of phenol with a composite carbon paste/polyamide electrode

The 2.5th order differential voltammetric behavior of phenol at a composite carbon paste/polyamide electrode in aqueous solution is reported. Adsorption of the phenol onto the electrode under open-circuit conditions is followed by application of the 2.5th order differential staircase sweep voltammetry. The results obtained under optimum conditions allowed the development of a method to determine phenol in the ranges of 1 × 10−5 to 6 × 10−5 mol 1−1, 1 × 10−6 to 1 × 10−5 mol 1−1, 1 × 10−7 to 1 × 10−6 mol 1−1 and 5 × 10−8 to 1 × 10−7 mol 1−1. The relative standard deviation is 2.2% for a concentration level of 5.6 × 10−6 mol 1−1and detection limit of 8.5 × 10−9mol 1−1 (RSD = 4.5%) was achieved. The effect of experimental conditions and the electrode mechanism were investigated. Good results were obtained by applying the proposed method to the determination of phenol in cola drinks.