title: Nanopillar Based Enhanced-Fluorescence Detection of Surface-Immobilized Beryllium.
abstract: The unique properties associated with beryllium metal ensures the continued use in many industries despite the documented health and environmental risks. While engineered safeguards and personal protective equipment can reduce risks associated with working with the metal, it has been mandated by the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) that the workplace air and surfaces must be monitored for toxic levels. While many methods have been developed to monitor levels down to the low μg/m(3), the complexity and expense of these methods have driven the investigation into alternate methodologies. Herein, we use a combination of the previously developed fluorescence Be(II) ion detection reagent, 10-hydroxybenzo[h]quinoline (HBQ), with an optical field enhanced silicon nanopillar array, creating a new surface immobilized (si-HBQ) platform. The si-HBQ platform allows the positive control of the reagent for demonstrated reusability and a pillar diameter based tunable enhancement. Furthermore, native silicon nanopillars are overcoated with thin layers of porous silicon oxide to develop an analytical platform capable of a 0.0006 μg/L limit of detection (LOD) using sub-μL sample volumes. Additionally, we demonstrate a method to multiplex the introduction of the sample to the platform, with minimal 5.2% relative standard deviation (RSD) at 0.1 μg/L, to accommodate the potentially large number of samples needed to maintain industrial compliance. The minimal sample and reagent volumes and lack of complex and highly specific instrumentation, as well as positive control and reusability of traditionally consumable reagents, create a platform that is accessible and economically advantageous.
authors.affiliation: †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.|‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Charlton
authors.affiliation: ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.|∥Northern Arizona University, College of Engineering, Forestry, and Natural Sciences, Flagstaff, Arizona 86011, United States.
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Jones
authors.affiliation: †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Wallace
authors.affiliation: ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Smithwick
authors.affiliation: †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.|‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Bradshaw
authors.affiliation: §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Kravchenko
authors.affiliation: §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States.
authors.forename: Nickolay V
authors.initials: NV
authors.lastname: Lavrik
authors.affiliation: †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sepaniak