EPA Method 23

Analytical testing dots

Incinerators - EPA Method 23Method 23 is used to determine the potential presence of polychlorinated dibenzo-p-dioxins (PCDD's) and polychlorinated dibenzofurans (PCDF's) in emissions from stationary sources.

The Clean Air Act Amendments of 1990 require the US EPA to regulate emissions of toxic air pollutants (hazardous air pollutants) using technology-based standards. These standards are known as the National Emissions Standards for Hazardous Air Pollutants (NESHAP) or the MACT (Maximum Achievable Control Technology) standards. EPA identified and compiled a list of the major sources of air toxics and established a timeframe in which MACT standards will be promulgated. When fully promulgated, approximately 170 source types will be affected. Industries affected by this regulation include paper mills, mineral smelters, electric utilities, solid waste incinerators, solid waste to energy systems, sewage sludge indinerators, cement kilns, and a variety other major source facilities.

Dioxin and furan emissions are included in the standards for several key industries using coal, fuel oil, and biomass. Numeric standards for dioxin and furan emissions have been issued for:

  • Commercial and industrial solid waste incinerators (solid waste incinerators, energy recovery incinerators, waste burning kilns, and small incinerators in remote locations)
  • Sewage sludge incinerators (multiple hearth and fluidized bed incinerators)
  • Industrial, commercial, and institutional boilers and process heaters at major source facilities (15 different categories; examples including Kraft recovery boilers and secondary copper smelters)

Sample collection media are prepared in the laboratory using pre-cleaned glass sampling traps and glass fiber filters. Glass traps are filled with pre-cleaned XAD resin. A surrogate standard containing a known amount of 5 labeled compounds is added to the XAD resin before the trap is packaged and shipped to the client for sampling.  The surrogate standard recoveries are calculated and reported as a measure of sampling efficiency.

When the sample is returned to the laboratory, the XAD resin, glass wool, and filter are combined in a soxhlet. An internal standard containing 9 labeled compounds is added before extraction. These labeled compounds are used to calculate the concentration of native (unlabeled) compounds in the sample as well as the surrogate standard recoveries. After extraction, but before clean up, the extract solvent is combined with any rinsate solvents and an alternate standard containing one labeled compound is added to measure clean-up efficiency. Sulfuric acid clean up is performed, followed by silica/carbon column clean-up. The extract is then transferred to an auto sampler vial and concentrated. A known amount of recovery standard is added to the extract prior to HRGC/HRMS (High-Resolution Gas Chromatography / High-Resolution Mass Spectrometry ). The sample extract is injected into a gas chromatograph coupled to a high-resolution mass spectrometer operating in SIM (select ion monitoring) mode.

Native Compounds

  • 2,3,7,8-TCDD
  • 2,3,7,8-TCDF
  • 1,2,3,7,8-PeCDD
  • 1,2,3,7,8-PeCDF
  • 2,3,4,7,8-PeCDF
  • 1,2,4,5,7,8-HxCDD
  • 1,2,3,6,7,8-HxCDD
  • 1,2,3,7,8,9-HxCDD
  • 1,2,3,4,7,8-HxCDF
  • 1,2,3,6,7,8-HxCDF
  • 1,2,3,7,8,9-HxCDF
  • 2,3,4,6,7,8-HxCDF
  • 1,2,3,4,6,7,8-HpCDD
  • 1,2,3,4,6,7,8-HpCDF
  • OCDD
  • OCDF

Internal Standards

  • C13-2,3,7,8-TCDD
  • C13-1,2,3,7,8-PeCDD
  • C13-1,2,3,6,7,8-HxCDD
  • C13-1,2,3,4,6,7,8-HpCDD
  • C13-OCDD
  • C13-2,3,7,8-TCDF
  • C13-1,2,3,7,8-PeCDF
  • C13-1,2,3,6,7,8-HxCDF
  • C13-1,2,3,4,6,7,8-HpCDF

Surrogate Standards

  • 37Cl-2,3,7,8-TCDD
  • C13-2,3,4,7,8-PeCDF
  • C13-1,2,3,4,7,8-HxCDD
  • C13-1,2,3,4,7,8-HxCDF
  • C13-1,2,3,4,7,8,9-HpCDF

Alternate Standards

  • C13-1,2,3,7,8,9-HxCDF

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