Soil Gas Sampler

Significance of the Topic

Sampling soil gas is essential for monitoring subsurface contamination and volatile organic compounds (VOCs). Reliable grab samplers enable accurate measurements of gas concentrations, reducing sample loss and leak risk. The soil gas sampler described here provides a streamlined, minimal-leak design with integrated flow control and filtration, supporting environmental assessment and regulatory compliance.

Objectives and Overview of the Article

This application note presents a compact soil gas sampler (cat.#22930-22949) engineered to connect directly to soil gas ports, incorporate a critical orifice for controlled flow, and simplify field operations. The aim is to detail its assembly, operation, maintenance, and available configurations to guide analysts in selecting the appropriate model for their sampling needs.

Methodology and Instrumentation

• The sampler integrates a stainless steel tee fitted with a precision orifice, a vacuum gauge (-30" Hg to 0" Hg), and a 2 µm frit filter held by a spring washer.
• Connections: ¼" compression inlet/outlet for easy coupling to canister valves and sample port tubing.
• Flow control: Orifice sizes (0.0065" to 0.0014") yield flows of 210 mL/min to 6 mL/min, enabling sample durations from 4 min to 10 h on standard canisters.
• Configurations: Kits available in Siltek-treated or stainless steel variants, with separate replacement tees and parts.

Key Results and Discussion

• Precision orifice design ensures consistent flow rates and predictable sampling intervals across multiple canister sizes.
• Integrated vacuum gauge allows real-time monitoring of pressure differential, enhancing sampling accuracy.
• Filter and washer assembly design prevents particulate ingress while remaining serviceable without specialized tools.
• Modular replacement parts reduce cost and downtime compared to complete sampler replacement.

Benefits and Practical Applications of the Method

• Minimized leak paths and simplified connections improve data quality in environmental site assessments and remediation programs.
• Wide range of flow rates accommodates various analytical requirements, from rapid screening to extended passive sampling.
• Robust materials and interchangeable components support field durability and cost-effective maintenance.

Future Trends and Opportunities

• Integration with digital pressure sensors and data loggers for automated remote monitoring.
• Development of multi-port multiplexed samplers to collect simultaneous profiles at different depths.
• Adoption of advanced filter materials to target emerging contaminants and ultra-low detection limits.

Conclusion

The Restek soil gas sampler family offers a versatile, low-leak solution for field sampling of VOCs and other soil gases. Its modular design, precise flow control, and integrated monitoring features provide analysts with reliable, cost-effective tools for environmental investigations.

Instrument Used

• Restek Soil Gas Grab Sampler, cat.#22930-22949; stainless steel tee with critical orifice, vacuum gauge, 2 µm frit filter.

References

No external literature references were provided in the original document.