(283c) Synthesis and Characterization of Analyte-Responsive Nanoparticles for the Detection of Polychlorinated Biphenyls

Polychlorinated biphenyls (PCBs) constitute a class of persistent organic pollutants (POPs) that, as a consequence of their high chemical stability and prevalent production in the early-to-mid 20th century, have accumulated in the environment, posing a significant threat to the health of exposed populations. As part of the efforts to identify and remediate heavily polluted areas, including Superfund sites, easily implemented methods to detect the concentration of PCBs in ground and surface water are necessary to appropriately determine the severity of contamination and designate the sites for quarantine and cleaning. Standard quantification as per Environmental Protection Agency (EPA) guidelines employs gas chromatography (GC) to discriminate and measure the type and concentration of POPs in a given sample, but the technique requires several preparatory extraction procedures that can mar the accuracy of results. GC systems are also time consuming, expensive, and often difficult to operate, altogether making them non-ideal for rapid, field-ready analysis of suspect samples. As a facile alternative, polymeric nanoparticles composed of poly(N-isopropylacrylamide) (PNIPAAm) formed with analyte-responsive domains present a solution-based approach for monitoring the presence of hydrophobic contaminants such as PCBs in aqueous environments. Metrics like turbidity permit visual identification of an analyte’s occupancy, and complementary analysis with ultraviolet-visible spectroscopy (UV-Vis) and dynamic light scattering (DLS) allow for quantification. Successful incorporation of comonomers (e.g., 4-vinylbiphenyl, 4-vinylaniline) into the nanoparticle network is evaluated using Fourier transform infrared spectroscopy (FTIR), and electron microscopy (EM) is used to verify the size distribution of the unswollen nanoparticles. Detection of hydrophobic contaminants with functionalized nanoparticles provides an easily implemented sensing method that is tunable for specific analytes with judicious selection of comonomers and adaptable for development into substrate-functionalized sensors.