(744f) Silica Fiber-Based Visible Colorimetric Method for on-Site Polycyclic Aromatic Hydrocarbon Detection

Aquatic ecosystems are a critical part of maintaining life on the planet. There are, however, many sources of contamination within the oceans—a large source of which being pollutants from oil spills. A common class of such pollutants is polycyclic aromatic hydrocarbons (PAHs), many of which are suspected of causing cancer and are regulated by the US Environmental Protection Agency (USEPA). The USEPA has set a total limit of 0.2 ppb of PAHs for safe, potable water. Here, a polymer fiber-based sensor is used for the detection of PAHs at concentrations applicable to those in the environment. The sensor is composed of a silica mat, whose surface properties prevent water reaching the colorimetric reaction chemistry, while the non-polar PAHs travel through the void space of the fibers. The silica fibers serve a dual purpose, as they also provide a substrate/reactant for the colorimetric chemistry to take place. To produce the fibers, DC needle electrospinning was employed. Formaldehyde, combined with an acid, condenses the fused ring structure of the PAHs to form qualitative brown colored quinoid compounds. To provide a quantitative sensor reading, a calibration curve based on the color intensity of the brown color. This portable and highly selective sensor provides an alternative to the traditional, expensive analytical equipment (HPLC, GC-MS), and allows for enhanced water monitoring of carcinogenic pollutants.