| Use: | Raman spectroscopy encompasses a variety of techniques that involve the detection and analysis of the scattering of radiation (see 6.2.17). |
Description:
Raman spectroscopy is the measurement of the wavelength and intensity of inelastically scattered light from molecules. When electromagnetic radiation passes through matter, most of the radiation continues in its original direction but a small fraction is scattered in other directions, as indicated below:
| Rayleigh scattering: | Light that is scattered at the same wavelength as the incoming light. |
| Brillouin scattering: | Light that is a scattered in transparent solid due to vibrations (photons). Typically shifted by 0.1 to 1 cm-1 from the incident light. |
| Raman scattering: | Light that is scattered due to vibrations in molecules or optical phonons in solids. Shifted by as much as 4,000 cm-1 from the incident light. |
Analytes:
1. Non-Halogenated VOCs
2. Non-Halogenated SVOCs
3. Halogenated VOCs
4. Halogenated SVOCs
5. PAHs
11. TPH
Media:
| Soil/Sediment | Water | Gas/Air |
| Requires extraction to a liquid or gas phase | BETTER | Requires extraction to a liquid or gas phase |
| Selectivity: | Technique measures a part of the compound. |
| Susceptibility to Interference: | High. |
| Detection Limits : | 100-1000 ppb (soil); 1-50 ppb (water). |
| Turnaround Time per Sample: | Minutes. |
Applicable To:
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Limitations:
ASTM Standards/EPA Methods:
No applicable ASTM standards or EPA methods are cited for this technology.
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