The adsorption of benzo[k]fluoranthene on self assembled films of octadecyltrichlorosilane

摘要

Organosilane compounds, such as octadecyltrichlorosilane (OTS), are commonly used in the formation of thin films for microelectronic, biosensor or chromatographic applications. In this paper, self-assembled OTS monolayer films were characterized by atomic force microscope (AFM) imaging and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Conditions to provide a monolayer free of OTS aggregates were established. These films were then exposed to aqueous solutions of benzo[k]fluoranthene (B[k]F), a carcinogenic polycyclic aromatic hydrocarbon (PAH) that is often present in both aqueous and terrestrial environments. Through the B[k]F associations with these OTS monolayer films, it was possible to obtain a film-solution partition coefficient (log K-fs) value of 7.0 +/- 0.1 using fluorescence detection, this value is :similar to partition coefficients previously observed in octanol-water systems. Using AFM images and fluorescence spectroscopy measurements, a maximum surface coverage or 9 (+/- 1) x 10(-4) molecules of B[k]F per Angstrom (2) was measured within these films, An upper limit to B[k]F concentration in solution was found, above which aggregates of B[k]F molecules were formed on the surface. [References: 32]