Electrochemical oxidation behavior of 2,4-dinitrophenol at hydroxylapatite film-modified glassy carbon electrode and its determination in water samples

Hydroxylapatite (HAP)-modified glassy carbon electrode (GCE) was fabricated and used to investigate the electrochemical oxidation behavior of 2,4-dinitrophenol (2,4-DNP) by cyclic voltammetry, differential pulse voltammetry, and chronocoulometry. The oxidation peak current of 2,4-DNP at the modified electrode was obviously increased compared with the bare GCE, indicating that HAP exhibits a remarkable enhancement effect on the electrochemical oxidation of 2,4-DNP. Based on this, a sensitive and simple electrochemical method was proposed for the determination of 2,4-DNP. The effects of HAP concentration, accumulation time, accumulation potential, pH, and scan rate were examined. Under optimal conditions, the oxidation peak current of 2,4-DNP was proportional to its concentration in the range from 2.0 × 10⁻⁶ to 6.0 × 10⁻⁴ M with a correlation coefficient of 0.9987. The detection limit was 7.5 × 10⁻⁷ M (S/N = 3). The proposed method was further applied to determine 2,4-DNP in water samples with recoveries from 96.75% to 106.50%.