Electrochemical enhancement of long alkyl-chained surfactants for sensitive determination of tetrabromobisphenol A

Three types of hydrophobic surfactants with one, two and three C18-alkyl chains, including octadecyltrimethylammonium bromide (OTMA), dioctadecyldimethylammonium bromide (DODMA) and trioctadecylmethylammonium bromide (TOMA), were used to construct sensing films for tetrabromobisphenol A (TBBPA). In pH 4.6 acetate buffer, an oxidation peak with low height is observed for TBBPA on the surface of glassy carbon electrode (GCE), and the oxidation wave increases greatly on the surfactant film-modified GCEs. Surface morphology analysis reveals that the modification of surfactants on GCE increases the surface roughness and introduces three-dimensional structures. Experiments of electrochemical impedance spectroscopy and chronocoulometry indicate that the electron transfer ability and accumulation efficiency of TBBPA enhance effectively on the surface of surfactant films. Moreover, the signal enhancement ability of surfactant films is heavily dependent on the molecular structures, and DODMA film is more active for the oxidation of TBBPA. As a result, a sensitive and simple electrochemical sensing platform was developed for TBBPA. The linear range is from 1.0 to 500 μg L−1, and the detection limit is 0.57 μg L−1 (1.05 nM). This new sensing system has been used to detect TBBPA in e-waste samples, and the results consist with the values that obtained by high-performance liquid chromatography.