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Analytical Methods and Sampling Guidance

Provides information on TPH methods 1005 and 1006, and on Method 5035. Also provides information on sampling.

Laboratory Accreditation

Analytical data relating to permitting or remediation and submitted to the TCEQ must be generated by a lab that is accredited through the Texas Laboratory Accreditation Program (TLAP) under the NELAP standard for matrices, methods, and parameters of analysis, unless:

  • The lab is an in-house lab and meets one of these criteria: The lab performs work for its owner, for another company with a unit located on the same site, or without compensation for a governmental agency or charitable organization, or the lab is in another state and is accredited or inspected by that state.
  • The lab is accredited under federal law.
  • The data are needed for emergency-response activities and no TLAP-accredited lab is available.
  • The lab supplies data for which we do not offer accreditation.

For permitting or remediation decisions, we will accept analytical data only if the data comply with all applicable rules for the regulatory program involved and:

  • the lab generating the data is NELAP-accredited by TLAP,
  • we have approved an exception as described above, or
  • the data were generated on or before June 30, 2008.

Required use of SW-846 Method 5035

Beginning January 1, 2016, the TCEQ Remediation Division will require the use of United States Environmental Protection Agency (USEPA) SW846 Method 5035 A, Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples, as amended, for the collection and preparation of solid samples for volatile organic compound (VOC) analysis using purge-and-trap technology. After December 31, 2015, the TCEQ Remediation Division will reject VOC data reported for solid samples, such as soil samples, collected and prepared using another method when the data are intended to demonstrate compliance with the rules in 30 Texas Administrative Code Chapters 334, 335, or 350.

Samples collected for VOC analysis must undergo preparation prior to analysis. The purge-and-trap procedure is the most common preparatory method for VOC analysis, e.g., analysis using SW846 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. Prior to 1997, preparation by purge-and-trap for both soil and water samples was outlined in Method 5030. In 1997, the USEPA revised SW846 to remove the soil component from Method 5030 and to introduce the new Method 5035 for solids. With that revision to SW846, the USEPA limited purge-and-trap preparation of solid samples to Method 5035, later revised to Method 5035A, and the purge-and-trap preparation of aqueous samples and sample extracts to Method 5030. Beginning on January 1, 2016, solid samples for VOC analysis must be collected and prepared using the Method 5035A procedures.

The TCEQ Remediation Division guidance on Method 5035 has been updated and is available. Please direct questions regarding Method 5035 or the guidance to the Technical Program Support Team at 512-239-2200 or by e-mail at

TPH Analytical Methods

TCEQ Method 1005 - This method involves analysis of an n-pentane extraction using gas chromatography followed by flame ionization detection. The method is to be used in the analysis of total petroleum hydrocarbons (TPH) having an approximate boiling point range between nC6 to nC28, or when applicable to the project objectives, nC6 to nC35. This method is applicable to soil, groundwater, and wastes. Revisions have been made to the method. The revised method is TCEQ Method 1005, Revision 03, effective as of June 1, 2001. The method allows the project objectives to be used to modify the method. General clarification and program specific guidance is provided in the document.

TCEQ Method 1006 - This method involves an n-pentane extraction followed by fractionation using a silica gel column and analysis using gas chromatography with flame ionization detection. The method is used to determine the distribution and concentrations of hydrocarbons in the aliphatic and the aromatic fractions of total petroleum hydrocarbons between the approximate boiling point range of C6 to C35. The method is applicable to soil, groundwater, and wastes. Under the TRRP rule, data from this method are used to establish the site-specific protective concentration levels (PCLs) at an affected property. This version is dated May 1, 2000.

This draft TCEQ Method 1006 should be used until a final version is issued. Laboratories that use these methods for TPH analysis, must keep on file the quality control data that demonstrate the laboratory is capable of performing the method. The laboratory also must have on file the data used to established the laboratory's quality control limits.

If you have any questions about the methods, please contact Technical Program Support.

Sampling Issues

Refer to this guidance on Sample Handling and Preservation Procedures and the Collection Procedures for Groundwater Samples.

Related Items

Industrial and Hazardous Waste Corrective Action Program

Texas Risk Reduction Program