2006 Progress Report: Rapid Detection of Trace Endocrine Disrupting Chemicals in Complex Mixtures: A Full-Spectrum Deconvolution Technique with a UV-Transparent Passive ConcentratorEPA Grant Number: R832738
Title: Rapid Detection of Trace Endocrine Disrupting Chemicals in Complex Mixtures: A Full-Spectrum Deconvolution Technique with a UV-Transparent Passive Concentrator
Investigators: Kibbey, Tohren C.G. , Sabatini, David A.
Institution: University of Oklahoma
EPA Project Officer: McOliver, Cynthia
Project Period: January 1, 2006 through September 30, 2010
Project Period Covered by this Report: January 1, 2006 through September 30, 2007
Project Amount: $448,259
RFA: Exposure Measurement Tools for Endocrine Disrupting Chemicals in Mixtures (2005) RFA Text | Recipients Lists
Research Category: Health , Safer Chemicals
The objective of this work is to develop a method for rapid monitoring and detection of endocrine disrupting chemicals (EDCs) at trace concentrations in natural waters using a full spectrum deconvolution technique with simultaneous absorbance and fluorescence measurements. The method will be coupled with a novel ultraviolet (UV)-transparent polymer-based concentrator to be used as a passive sampling device. The UV-transparent polymer-based concentrator will serve both as a solid phase extraction medium to concentrate EDCs for analysis and exclude many compounds likely to interfere with detection (fines, macromolecules such as organic matter, ionic surfactants), and as an analytical optical cell, allowing rapid EDC quantification without labor-intensive pre-concentration procedures. The work is divided into three primary tasks:
- Task 1: Development of the deconvolution method and measurement of basis spectra.
- Task 2: Development of the UV-transparent polymer concentrator.
- Task 3: Validation of the method.
We have been making excellent progress in the first project year on the proposed work. To date, emphasis has been on Task 2, polymer selection and characterization. To date, five polymers have been selected for testing, and preliminary testing has been conducted. We have also selected 25 suspected EDCs for initial testing, and have conducted experiments with 17 of them to date. This list will be expanded in coming project years as we finalize our polymer selection and move on to measurement of basis spectra (Task 1, subtask 3). In addition to the work on Task 2, we have begun assembling synthetic wastewaters for preliminary testing of interferences (Task 3). Wastewaters are being prepared following data found in the National Aeronautics and Space Administration (NASA) Advanced Life Support Baseline Values and Assumptions Document. The document contains detailed analyses of specific waste streams, some of which contain 60 or more individual components. These model waters will provide a controlled, yet highly complex, background for testing the method. Work with synthetic wastewaters will be a prelude to our ultimate efforts of testing with EDC-contaminated natural waters.
Preliminary work has emphasized the polymer (polydimethylsiloxane [PDMS]) which appears to have a good combination of properties for the work. Initial results show reasonable partitioning coefficients for many compounds. Ongoing work is aimed at further improving detection limits.
We will continue conducting experiments as described above, following the plan outlined in the original proposal. Ongoing work will begin examining the use of fluorescence detection to improve detection limits, as well as methods of determining basis spectra for DEG1, DEG2, and DEG3 (which appear to have higher partition coefficients, and as such, lower detection limits). Work developing optical cells with quartz windows is planned, to improve detection limits by eliminating cuvette absorbance, allowing longer polymer path-lengths. In addition, work will begin to emphasize further method development (Task 1) to improve selectivity and rejection of unknowns, as described in the original proposal.