Analysis of VOC Gases and TO-1/TO-2 Standards via Dynatherm 9300 TDA Using VOCGAS Focussing Trap

Significance of the Topic

The reliable detection of volatile organic compounds (VOCs) and TO-1/TO-2 gas standards at trace levels is critical for environmental monitoring, workplace safety and regulatory compliance. Cryogen-free thermal desorption methods minimize cost and complexity while preserving analytical performance.

Objectives and Study Overview

This study introduces a novel 2 mm focusing trap integrated into the Dynatherm 9300 Thermal Desorption system. It aims to demonstrate cryogen-free analysis of individual VOCs and TO-1/TO-2 standards at 100 ng/µL, comparing its performance to a conventional GC cryo approach.

Methodology

Analytical tubes (6 mm) packed with Tenax TA, Carboxen 1000 and Carbosieve SIII were spiked with 1 µL of each standard. Tubes were desorbed at 325 °C (3 min) onto the focusing trap held at 35 °C. Trap desorption occurred at 300 °C (5 min) under 48 mL/min helium, followed by transfer to GC.

Instrumentation

• Dynatherm 9300 TDA with autosampler
• Cryogen-free 2 mm focusing trap
• Varian 3800 Gas Chromatograph
• Varian Saturn 2000 Ion Trap detector
• CP Select 624 column (30 m × 0.25 mm × 1.4 µm)

Main Results and Discussion

The trap captured and released all target VOCs and TO-1/TO-2 analytes with chromatographic performance matching a GC cryo oven (−50 °C start). Peak shapes and resolution of chlorinated compounds remained excellent. Methanol co-analysis generated ion trap interference, obscuring chloroethane and bromomethane, but overall separation was robust.

Benefits and Practical Applications

• Eliminates cryogen handling and associated costs
• Reduces maintenance and operational complexity
• Maintains sensitivity and resolution for regulated VOC analyses
• Supports automated, high-throughput environmental and industrial monitoring

Future Trends and Potential Applications

Cryogen-free focusing traps are poised to expand in air quality assessment, workplace exposure studies and petrochemical leak detection. Coupling with GC-FTIR, multiplexed traps or field-portable platforms could enable wider compound coverage and near real-time ambient analysis.

Conclusion

The 2 mm focusing trap on the Dynatherm 9300 TDA offers a practical, cryogen-free solution for trace VOC and TO-1/TO-2 gas analysis. It delivers performance on par with cryo-cooled methods while streamlining workflow and reducing costs, making it well suited for routine trace gas monitoring.

References

No external literature references were provided in the source application note.