EPA TO1 Analysis using the CDS TDA 9300 Autosampler

Significance of the Topic

Volatile organic compounds (VOCs) emitted from industrial, commercial and waste storage sites pose serious risks to human health and the environment. Reliable qualitative and quantitative analysis of nonpolar VOCs in the boiling point range 80–200 °C is essential for regulatory compliance, workplace safety and process monitoring.

Objectives and Overview of the Study

This application note demonstrates an automated method for EPA TO-1 analysis of nonpolar VOCs using multibed thermal desorption tubes coupled to GC/MS. The goals were to achieve sensitive, linear detection of target analytes and to validate the approach for routine environmental monitoring.

Instrumentation

• TDA 9300 thermal desorption autosampler
• Multibed sampling tubes packed with Tenax TA, Carboxen 1000 and Carbosieve SIII
• ACEM 9300 gas chromatograph interfaced to a mass spectrometer detector

Methodology

A commercial TO-1 stock standard (2000 µg/mL in methanol) was diluted to 25 ng/µL working standard. Multibed tubes were spiked with concentrations of 25, 50, 75, 100, 150 and 200 ng of the standard, each in triplicate. Tubes were desorbed in the TDA 9300 at 225 °C for 5 min, with trap desorption at 250 °C for 2.5 min. Desorbed analytes were transferred under helium carrier into the GC/MS for separation and mass spectral detection.

Main Results and Discussion

The technique produced clear qualitative chromatograms for the TO-1 analyte mix. Benzene calibration over 0–200 ng showed excellent linearity (R2 = 0.9978). A total of 17 EPA TO-1 compounds—ranging from allyl chloride to o- and p-xylenes—were successfully separated and identified. High sensitivity and reproducibility were observed across concentration levels, demonstrating robustness of the thermal desorption and GC/MS interface.

Benefits and Practical Applications

• Automation improves throughput and repeatability for large sample batches
• Multibed sorbent tubes efficiently capture a wide range of nonpolar VOCs
• Thermal desorption eliminates solvent use and reduces background interference
• Method meets EPA TO-1 regulatory requirements for environmental monitoring and site assessment

Future Trends and Potential Applications

Integration of infrared detection (GC-IR) with thermal desorption and GC/MS will enable simultaneous chemical structure confirmation and quantification. Advances in sorbent technology, miniaturized autosamplers and high-resolution mass spectrometry may further enhance sensitivity and selectivity. The approach may be extended to complex matrices, polymer characterization and on-site field analysis.

Conclusion

The described automated EPA TO-1 method using multibed thermal desorption tubes and GC/MS provides a sensitive, linear and reproducible tool for nonpolar VOC analysis. Its compliance with regulatory protocols and adaptability for high-throughput laboratories make it well suited for environmental monitoring and industrial process control.

References

No external literature references were cited in the application note.