This is the second post in our Method 5035 Blog Series. The first post focused on the TCEQ Regulatory Update, and subsequent blog posts will focus on Texas/TCEQ-specific requirements of Method 5035, followed by sampling and analytical considerations and best practices.
Nineteen years after Method 5035 was published in the US EPA’s SW-846, confusion continued/continues in some states about the proper sample containers to be used for the collection of soils and wastes for volatile organic compound (VOC) analysis.
Samples collected for VOC analysis (including oxygenates) in soil and solid wastes (e.g., TCL VOAs, BTEX, GRO) by either GC or GC/MS must undergo preparation prior to analysis. The purge-and-trap procedure is the most common preparatory method for VOC analysis (e.g., analysis using SW-846 Methods 8260, 8021, and 8011). Method 5035A describes the procedures for collecting solid samples and preparing the samples for VOC analysis using purge-and-trap technology.
While the method is designed for use on samples containing low levels of VOCs, optional procedures are also provided for collecting and preparing solid samples containing high concentrations of VOCs and for oily wastes. The specific preparation procedures for sample vials depend on the expected concentration ranges of the sample; there are separate and distinct preparation procedures for low-concentration soil samples and for high-concentration soil and solid waste samples.
Prior to 1997, preparation by purge-and-trap for both soil and water samples was outlined in Method 5030. Soil samples were traditionally collected in 2 or 4-ounce wide mouth glass jars by packing the soil sample in the jar to limit the amount of headspace in an attempt to prevent loss of VOCs. A small portion (normally 5 grams) was physically removed from the jar and a direct analysis by purge and trap was performed. This technique resulted in physical manipulation of soil samples in an open air environment. In 1997, the US EPA revised SW-846 to remove the soil component from Method 5030 and to introduce the new Method 5035 for solids. With that revision to SW-846, the US EPA limited preparation of solid samples to a closed system purge-and-trap (eliminating subsampling from a wide mouth jar) to Method 5035, later revised to Method 5035A, and the purge-and-trap preparation of aqueous samples and sample extracts to Method 5030.
The state of Texas is the latest to formally adopt Method 5035A. If you have operations and site responsibility in Texas, beginning on January 1, 2016, solid samples for VOC analysis must be collected and prepared using the Method 5035A procedures.
Check back for future blog posts in our Method 5035 series as we cover:
- Method 5035 Texas-Specific Requirements
- Method 5035 Sampling, Analytical Considerations & Best Practices