Laboratory-Based Air Monitoring Solutions from Agilent Technologies

Importance of the Topic

Accurate measurement of volatile organic compounds in air is critical across environmental research, industrial hygiene, workplace safety, and indoor air quality. Thermal desorption (TD) coupled with gas chromatography–mass spectrometry (GC/MS) offers high sensitivity, broad compound coverage from sub-ppt to ppm levels, and compatibility with diverse sampling media. With increasing regulatory strictness for air toxics, fugitive emissions, vapor intrusion, stack testing, and personal exposure, robust, cryogen-free TD-GC/MS solutions are essential for reliable monitoring and compliance.

Objectives and Overview

This compendium presents a series of application briefs for Agilent’s TD-GC/MS systems developed in partnership with Markes International. It demonstrates method compliance with international standards (U.S. EPA TO-15/17, ISO/EN 16017, ASTM D6196, EN 14662, NIOSH 2549), highlights automation options, and showcases successful analyses across seven key areas: air toxics, hazardous air pollutants, soil gas and vapor intrusion, stack emissions, occupational hygiene, fugitive and fence-line monitoring, and indoor air quality.

Methodology

Each application uses sorbent tubes, canisters, passive samplers or bags to capture organics. Samples are thermally desorbed in a two-stage trap focusing system, then analyzed on an Agilent 7890A GC interfaced to a 5975C MSD. Cryogen-free operation, electronic tube tagging, and optional SecureTD-Q allow re-collection and enhanced traceability. Typical TD parameters include desorption at 300–320 °C, focusing traps at sub-ambient to 300 °C, and split ratios up to 5000:1 for high-concentration samples.

Used Instrumentation

• Series 2 UNITY and ULTRA thermal desorption units with Canister Interface Accessory
• Agilent 7890A gas chromatograph with Electronic Pneumatic Control
• Agilent 5975C MSD with inert source, triple-axis HED-EM detector, heated quartz analyzer
• Variety of sorbent tubes (Tenax, Carbograph, hydrophobic soil-gas), Silcosteel canisters, Tedlar bags
• Columns: J&W DB-624, DB-5ms, HP-5 MS, DB VXR
• Optional accessories: TubeTAG electronic tagging, bio-VOC breath sampler, diffusive caps

Main Results and Discussion

Sub-100 ppt detection limits and linear response from 0.1 to 25 ppb were demonstrated for 62 air toxics. Repeatability (<5 % RSD) was achieved for target analytes spanning C2 to C40. Soil-gas tubes outperformed canisters in recovering middle-distillate fuel vapors. Stack-gas applications using double splitting produced consistent mass results across replicate analyses. Occupational and indoor air studies detected amines, solvents, aromatic hydrocarbons, and higher boiling VOCs in real-world samples, illustrating method versatility.

Benefits and Practical Applications

• Cryogen-free TD simplifies maintenance, reduces cost and water management issues
• Automated workflows with unattended multi-tube or canister sequencing
• SecureTD-Q enables re-analysis and validation without sample loss
• Electronic tagging supports chain-of-custody in high-throughput labs and field studies
• Wide compliance with global standards ensures acceptance in regulatory environments

Future Trends and Opportunities

Advances will focus on miniaturized, field-deployable TD-GC/MS systems, improved high-throughput automation, and software-driven data mining to identify emerging air pollutants. Integration with real-time sensors and IoT networks could enable continuous monitoring. Breath analysis and bio-monitoring will expand for non-invasive exposure assessment.

Conclusion

Agilent’s TD-GC/MS platforms, in collaboration with Markes International, deliver flexible, sensitive, and compliant solutions for a broad spectrum of air monitoring challenges. Cryogen-free operation, two-stage focusing, and sample re-collection capabilities maximize productivity and data integrity across environmental, industrial, and occupational applications.

References

• Agilent Technologies. Laboratory-Based Air Monitoring Solutions: Application Compendium. 2009.