Electrochemical detection of catechol with a disposable carbon nanotube paste electrode modified with CTAB

The accurate and rapid detection of catechol which is a class of highly toxic organic phenolic compounds, is of great importance for the protection of environment and human health. In this work, a novel electrochemical sensor for catechol was constructed by modifying multi-walled carbon nanotube paste microelectrode with a cationic surfactant of cetyltrimethylammonium bromide (CTAB) through a simple and controllable adsorption method. Electrochemical experiment results show that the modified electrode has good sensitization effect to the electrochemical response of catechol. The electrochemical response mechanism of the sensor to catechol were investigated through using many analytical methods, including scanning electron microscopy, energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and electrochemical techniques. Under the optimal fabrication and application conditions, the response current of catechol on the sensor exhibits a good linear relationship with its concentration from 1.0 μmol l−1 ∼ 7.0 mmol l−1 with a sensitivity of 1.33 nA/(μmol l−1) and a low detection limit of 15 nmol l−1 (S/N = 3). Applying the sensor in the detection of catechol in tap water samples and urine samples, the results were satisfactory, indicating its good application prospect.