Thermal Desorption Tubes with Unique Barcodes

Significance of the Topic

Thermal desorption tubes with unique barcodes represent a major advancement in sampling and analysis of volatile and semi-volatile organic compounds. They offer improved traceability, consistent back pressure, and compatibility with established environmental methods. The integration of multi-bed adsorbent configurations enables broad compound coverage from C2 to C30, supporting both active and passive monitoring scenarios.

Objectives and Study Overview

This overview examines the design, performance, and applications of barcoded thermal desorption tubes developed by Supelco. Key goals include ensuring batch-to-batch consistency, enhancing sample handling via TDS3 storage containers, and validating passive diffusive monitoring for fenceline benzene and other VOCs in compliance with US EPA methods.

Methodology

The tube series are classified by the number of adsorbent beds: single (100 series), dual (200 series), triple (300 series) and four beds (400 series). Adsorbents include Carbotrap B and C, Carboxen and Carbopack grades, glass beads and specialized media like Graphsphere. Performance metrics include sampling rates, uptake efficiency under varying humidity and temperature, and recovery by thermal desorption coupled to gas chromatography with mass spectrometric detection.

Instrumentation

Key devices and accessories used:

• TDS3 storage and sampling containers for contamination-free handling
• Stainless steel and glass-fritted tube formats with preconditioned or unconditioned options
• Escort ELF and GEMINI twin port sampling pumps for controlled flow rates
• Model 1067 dual-channel ambient air sampler for EPA TO-17 compliance
• PAS-500 micro air sampler for low-flow industrial hygiene applications
• VOST tubes meeting SW-846 Method 0030 requirements

Main Results and Discussion

Studies demonstrate highly reproducible sampling rates across tubes, with deviations within 10 percent for key VOCs at 75 percent relative humidity. Passive diffusive sampling using deactivated Carbopack X SS tubes yields validated uptake rates for benzene and other target analytes under EPA Method 325B. Back pressure consistency and barcode traceability ensure reliable QA QC throughout the sampling chain.

Benefits and Practical Applications

The barcoded tubes and supporting hardware deliver several advantages:

• Guaranteed adsorbent authenticity and quality when sourced from the production facility
• Easy-read markings and resistant barcodes for field logistics
• Broad analyte range from light gases to semi-volatiles in air, water and solids
• Compatibility with standard EPA, NIOSH, ASTM and MDHS methods
• Elimination of dead volume and reduced contamination risk via TDS3 containers

Future Trends and Applications

Emerging directions include integration of tube barcodes with digital chain-of-custody platforms, development of novel sorbent materials for ultra-volatile compounds, and miniaturized systems for real-time fugitive emission monitoring. Advances in high-throughput thermal desorption and online GC-MS will further streamline environmental and industrial safety assessments.

Conclusion

Barcoded thermal desorption tubes represent a versatile and robust solution for comprehensive VOC sampling. Their consistent performance, traceability and method compliance support diverse applications from regulatory monitoring to industrial hygiene. The combination of multi-bed adsorbents and streamlined sample handling enhances data quality and operational efficiency.

References

• Federal Register 2014. Petroleum Refinery Sector Risk and Technology Review and New Source Performance Standards; Proposed Rule. Volume 79, pages 36880–37075.
• Brown JL, Betz WR, Sidisky LM, Keeler MJ, Oliver KD, Jacumin HH Jr, Daughtrey EH Jr. New Carbopack X metal-passivated adsorbent tube for 24-hour diffusive sampling of 1,3-butadiene and additional VOCs. PittCon 2008.
• Thoma ED, Miller MC, Chung KC, Parsons NL, Shine BC. Facility fence-line monitoring using passive samplers. J Air Waste Manag Assoc. 2011;61:834–842.
• McClenny WA, Jacumin HH Jr, Oliver KD, Daughtrey EH Jr, Whitaker DA. Comparison of 24 h averaged VOC monitoring results using Carbopack X diffusive samplers and active sampling. J Environ Monit. 2006;8:263–269.
• McClenny WA, Oliver KD, Jacumin HH Jr, Daughtrey EH Jr, Whitaker DA. Diffusive sampling of toxic VOCs on Carbopack X with thermal desorption GC/MS. J Environ Monit. 2005;7:248–256.