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Semi-Volatiles

Semi-Volatiles

Semivolatile Organic Compounds

Semivolatile Organic Compounds (SVOCs) are similar to VOC compounds in that they can vaporize from liquid or solid forms. However, SVOCs have a lower vapor pressure and boiling point, and cannot be quantified using purge and trap methods. Common SVOC compounds include polynuclear hydrocarbons, phthalates, phenol and nitrobenzene. SVOC compounds are subject to many of the same regulatory programs as VOCs on both state and federal levels.

SVOC compounds can traditionally be split into three categories; bases, neutrals and acids. Compounds are placed into these categories based upon how they are extracted – bases and neutrals are extracted using a chemical with a pH > 7, whereas acids are extracted with a chemical with a pH < 7. Often, SVOC compounds are further divided into a category of 16 compounds called polynuclear aromatic hydrocarbons (PAHs), which are the byproducts of the combustion of coal, oil, wood or similar products.

TestAmerica analyzes SVOC samples utilizing GC/MS technology to generate chromatograms that are used to identify and quantify compounds of concern. With certifications covering all states where certification is offered, TestAmerica offers SVOC analyses by methods such as 8270, 8270_SIM, 625 and TO-13.  Many TestAmerica labs also offer SVOC analyses for water samples using our Lower Volume Initiative to reduce the sample volume required for extraction from 1000 ml to 250 ml.  To learn more, please visit our Lower Volume Initiative page.  

PAHs, Alkylated and Parent

Low-level GC/MS PAH and Alkyl-PAH analysis have traditionally been performed with the mass spectrometer operating in the selected ion monitoring (SIM) mode. This approach has been applied on many large scale studies, including NOAA Status and Trends Mussel Watch, the Exxon Valdez Oil Spill (EVOS), Housatonic River and the US Fish and Wildlife Natural Resources Damage Assessments. While this approach is useful in gauging bulk soil and sediment contamination, and in identifying the sources of contamination, the risk of false positives (and positive bias) in this analysis has been accepted as a trade-off for increased sensitivity offered by SIM.

Working with recent improvements in GC/MS technology, coupled with experience in extract purification techniques, TestAmerica developed both SIM and full scan low-level GC/MS PAH analyses. The full scan method preserves the mass spectral matching quality of the regulatory methods. This method balances the need for low detection limits with the need for better qualitative and quantitative certainty. The method is based on method 8270C and NOAA Technical memorandum NOS ORCA 130.  TestAmerica's full scan method covers all PAHs and Alkyl PAHs that are as follows:

  • Listed by USEPA Methods 8270C and 625
  • Recommended by the USEPA for predicting toxicity via the narcosis model
  • Listed by USEPA’s Integrated Risk Information System (IRIS)
  • Required by current and past NOAA Status and Trends Statements of Work
  • Listed in sediment quality guidelines by NOAA SQuiRT
  • Required by US Fish and Wildlife Organics Statement of Work
  • Assigned toxic equivalency factors by USEPA and the USFDA

PAHs, Passive Sampling

Traditional analytical methods for PAHs in sediment materials measure suspended sediment and colloidal content along with the freely dissolved chemicals. As a result, these protocols often report levels of chemicals in water samples that far exceed their maximum solubility. Surface and pore waters contain particulate and colloidal materials. These suspended materials have significant levels of contaminants that are not bioavailable. Current passive samplers supported include passive diffusion bags, SPMD, POM, PE, PDM and SIREM.  SiREM has partnered with TestAmerica to offer a comprehensive passive sampling service for measuring available hydrophobic organic compounds in sediment/sediment porewater, surface water, and soil.  SiREM currently offers both “off the shelf” and customizable passive sampling services for PAHs that includes:

  • Rugged, field-tested, ready-to-deploy in situ samplers
  • PAH (EPA 8270 Mod) analysis through TestAmerica
  • Processing of sampler data to provide results on a dissolved phase basis (e.g., ng PAH/L porewater).

For more information on TestAmerica’s SVOC offerings, please click on the following links to view our capabilities, which can be further filtered by lab, method, program or technique, and our certifications.