Polycyclic Aromatic Hydrocarbon Detection by Electrochemiluminescence Generating Ag/TiO2 Nanotubes

Highly ordered TiO2 nanotube arrays are with unique photoelectrical properties due to their highly ordered nanostructure and the resulted short charge transportation path. We report, for the first time, on the application of Ag nanoparticle-modified TiO2 nanotubes (Ag/TiO2 NTs) in the electrochemiluminescence detection of polycyclic aromatic hydrocarbons (PAHs) using the Ag/TiO2 NT film as working electrode and S2O82- as coreactant, with benzo(a)pyrene (BaP) as the model compound. The hydrophobic BaP absorbs onto the TiO2 NTs surface, and oxidized with consumption of the excited TiO2 (TiO2 star+) resulting in a decrease in ECL. Under the optimal conditions, a detection limit of 1.0 x 10(-12) M is achieved with a linear range of 3.0 x 10(-12) similar to 1.0 x 10(-9) M. Compounds which can not be oxidized by the excited TiO2 (TiO2 star+), such as benzene, naphthalene (NAP), anthracene (ANT), and tris-2,3-dibrominepropyl isocyanurate (TBC) show little interference on the detection, whereas PAHs with more than four rings can be detected by the proposed method.