Subtask 1.12 - Solid-Phase Microextraction (SPME) Coupled with Optical Spectroscopy for Near-Real-Time Determination of Fuel and Related Pollutants in Water Samples: Semi-annual report, July 1--December 31, 1996

摘要

The measurement of organic pollutants in water requires that samples be collected, transported to a laboratory, extracted (usually with large volumes of hazardous chlorinated solvents), and analyzed using chromatographic techniques. Such limitations make rapid determinations in the field (e.g., for emergency response and/or for survey investigations) very expensive with analytical turnaround times requiring several days. Similar limitations exist for the collection and analysis of organic pollutants in air. An alternative approach is being developed at the Energy (ampersand) Environmental Research Center (EERC) that has been demonstrated to yield good sensitivities (ppb to ppm) and be easily adapted for rapid (less than 30 minutes) and inexpensive field surveys. This new approach is based on the preconcentration of organic pollutants in optically clear sorbent media followed by measurement with either ultraviolet (UV) spectroscopy or Fourier transform infrared spectrometry (FT-IR). Investigations using sorbent media including methylsilicone gums (for UV spectroscopy) and 'Parafilm' (for FT-IR) have shown that quantitative determinations of aromatic fuel components, such as benzene and alkylbenzenes (BTEX), can be achieved using UV spectrometry, and of common solvents (e.g., chloroform and other chlorinated solvents) can be achieved using FT-IR. Sample concentration and spectroscopic steps can be performed in a few minutes using the combination of solid-phase sorption followed by spectroscopic measurements. This work has demonstrated that the approach can yield low-ppm to low-ppb detection limits for organic pollutants in water without the negative influences of water matrix components (e.g., dissolved humic material) that prohibit the use of direct spectroscopic measurements.