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ION COMPOSITION ELUCIDATION (ICE): A HIGH RESOLUTION MASS SPECTROMETRIC TECHNIQUE FOR CHARACTERIZATION AND IDENTIFICATION OF ORGANIC COMPOUNDS
Citation:
Grange, A H. AND G W. Sovocool. ION COMPOSITION ELUCIDATION (ICE): A HIGH RESOLUTION MASS SPECTROMETRIC TECHNIQUE FOR CHARACTERIZATION AND IDENTIFICATION OF ORGANIC COMPOUNDS. Presented at American Chemical Society, 221st National Meeting, San Diego, CA, April 1-5, 2001.
Impact/Purpose:
The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.
Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCPs. Application and improvement of analytical methodologies that can detect non-volatile, polar, water-soluble pharmaceuticals in source waters at levels that could be environmentally significant (at concentrations less than parts per billion, ppb). IAG with USGS ends in FY05. APM 20 due in FY05.
Subtask 2: Coordination of interagency research and public outreach activities for PPCPs. Participate on NSTC Health and Environment subcommittee working group on PPCPs. Web site maintenance and expansion, invited technical presentations, invited articles for peer-reviewed journals, interviews for media, responding to public inquiries.
Subtask 3: To apply state-of-the-art environmental forensic techniques to the recognition and characterization of emerging pollutants in the aquatic environment. There is a need for high sensitivity and for a powerful method of structural characterization, advanced mass spectrometric and chromatographic techniques to be employed to meet the challenge of emerging pollutants, including pharmaceuticals and personal care products, agents of sabotage, and explosives. Ongoing efforts continue to identify previously unrecognized pollutants from a range of problematic samples having importance to regional and state contacts.
Subtask 4: To provide the Agency with a set of practical analytical methods for the selective and sensitive determination of selenium species (organic, inorganic, volatile and non volatile forms) in multiple media to accurately assess and if necessary control the risk of selenium exposure to organisms. This includes development of optimal extraction, digestion, separation and detection approaches.
Subtask 5: To develop and apply an analytical method that can extract and detect synthetic musks. The extent of exposure may be determined by measuring levels of synthetic musks from their potential source (communal sewage effluent). This subtask ends in FY05 with the deliverable of APM 21. Future applications to biosolids will be covered in subtask 6.
Subtask 6: Application, and improvement, of previously in-house developed sensitive, robust, and green, methodologies regarding the use of urobilin and sterols as a possible markers of sewage contamination.
Subtask 7: Adaptation and improvement of previously developed in-house methods, for PPCPs (e.g., antibiotics and musks) to solid materials (e.g. biosolids, sediments).
Subtask 8: Study of the presence of personal care products, incombustible organic compounds from the direct-piping of small engines exhaust in Lake Tahoe, and lake deposition of airborne pollutants from industrial activity
Description:
Identifying compounds found in the environment without knowledge of their origin is a very difficult analytical problem. Comparison of the low resolution mass spectrum of a compound with those in the NIST or Wiley mass spectral libraries can provide a tentative identification when the mass spectrum is free of interferences, at least several prominent ions are observed in the mass spectrum, the mass spectrum is in the library, and only one plausible match is found. Because these libraries contain only 226,334 distinct compounds (1) compared to the 16 million compounds that have been synthesized or isolated from natural sources (2), most compounds are not found in the libraries. In addition, most compounds are ionic, too polar, too thermolabile, or too high in mass to traverse a GC column or to volatilize from a probe. For these compounds, liquid sample introduction with electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) provides few fragment ions for pattern matching, and adduct ions complicate the mass spectra. Commercial ESI and APCI mass spectral libraries are not available. Consequently, low resolution mass spectrometry cannot identify most compounds-.