Analyzing Stack Gas Semivolatiles, Using Supelpak-2 Adsorbent and Capillary GC (Modified Method 5, US EPA SW-846)

Significance of the Topic

Accurate monitoring of semivolatile organic compounds in stack emissions is essential for regulatory compliance and public health protection. High-purity adsorbents that deliver low background contamination are critical to achieve the stringent detection limits required by EPA methods.

Objectives and Study Overview

This application note evaluates Supelpak-2 adsorbent for Modified Method 5 (US EPA SW-846 Method 0010) sampling trains. It demonstrates cleaning protocols, background performance, and comparison with conventional XAD-2 material for sampling polynuclear aromatic hydrocarbons (PAHs) and other semivolatiles.

Methodology

Supelpak-2 cartridges are solvent cleaned and tested to ensure total background semivolatiles below 4 μg/g per Method 0010. During sampling, air is drawn through the packed cartridges at >20 L/min to collect gas- and particle-bound compounds. Post-sampling, analytes are extracted with methylene chloride, the extract is concentrated, and analysis is performed via capillary GC with FID, MS, or HPLC/UV.

Used Instrumentation

• Sampling train with glass cartridge packed with Supelpak-2 adsorbent
• Capillary GC column SPB-5, 30 m × 0.53 mm ID, 0.50 μm film
• GC/FID system: injector 220 °C (1 μL direct injection), detector 320 °C; carrier He 6 cc/min with N₂ makeup 40 cc/min
• Oven program: 40 °C (4 min) → 300 °C at 15 °C/min, hold 4 min

Main Results and Discussion

Cleaned Supelpak-2 exhibited a total chromatographable organics (TCO) background of 0.06 μg/g, far below the 4 μg/g blank requirement. In contrast, another cleaned XAD-2 sample showed 18 μg/g TCO. The low stable background enables reliable quantification of target semivolatiles. Surrogates such as 2-fluorobiphenyl and standards like heptane and perylene-d₁₂ serve as retention markers and quantify extraction efficiency.

Benefits and Practical Applications

• Exceptional low-blank performance enhances detection limits
• Compatibility with GC/FID, GC/MS, and HPLC/UV workflows
• Applicability in stack gas, ambient air, and indoor air PAH monitoring
• Custom purification services available for specialized sampling requirements

Future Trends and Potential Uses

Future developments may integrate Supelpak-2 in automated sampling systems, extend the analyte range to emerging semivolatiles, and pair with high-resolution mass spectrometry for detailed speciation. Advances in adsorbent materials may target lower volatility compounds and nanoparticle-bound organics.

Conclusion

Supelpak-2 meets stringent EPA background criteria and delivers reproducible, low-blank performance for semivolatile sampling in stack emissions. Its robust compatibility with standard analytical methods makes it a valuable tool for environmental monitoring and regulatory compliance.

References

• US EPA SW-846 Method 0010 (Modified Method 5)
• US EPA SW-846 Method 0020 (Source Assessment Sampling System)
• EPA TO-13 (PAHs in Ambient Air)
• EPA IP-7 (PAHs in Indoor Air)