(117v) Nanofiber Based Colorimetric Sensors for the Detection of Organic Analytes in Complex Environmental Media

Drinking water is often exposed to contamination through industrialization. Trihalomethanes (THMs), are among the most common contaminants, being by-products of water chlorination/treatment. The carcinogenic and health effects of these compounds have motivated scientists to work on the accurate detection of THMs down to 80 ppb in treated water. Here, a superhydrophobic syndiotactic polypropylene (sPP) nanofiber mat produced via electrospinning is used to preconcentrate THMs in environmental water samples, and subsequently, detect them using a well-known colorimetric reaction chemistry. The reaction chemistry yields a visible red/pink chromophore under visible light absorption. This reaction occurs when the preconcentrated THM becomes trapped in the liquid phase of the reaction chemistry, on the surface of the sPP fibers. The resulting color change can be analyzed via a simple quantitative color intensity analysis utilizing widely-available software, measuring the THM content in water as low as 0.8 ppb. Similarly, polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds resulting from oil spills and industrial pollution, and are capable of causing long-term health damage. Herein we demonstrate the first nanofibrous polymer-based on-site colorimetric sensor for the detection of PAHs at environmentally-relevant concentrations. Electrospinning is used to create silica nanofibers, formaldehyde, under acidic conditions, is used to colorimetrically detect the PAHs—reacting to form brown quinoid compounds on top of the white silica fiber mat. This robust and portable sensor is an uncomplicated alternative to the traditional, expensive analytical equipment (HPLC, GC-MS), and allows for on-site and rapid water monitoring.