TO--17 Anallysiis usiing tthe CDS TDA 9300 Auttosampllerr

Importance of Topic

EPA Method TO-17 is a widely adopted protocol to quantify volatile organic compounds (VOCs) in ambient air using sorbent tube sampling and thermal desorption followed by gas chromatography–mass spectrometry, playing a key role in air quality management and regulatory compliance.

Study Objectives and Overview

This application note demonstrates the performance of the CDS TDA 9300 autosampler coupled to a GC–ion trap system for TO-17 analysis of a 65-component VOC standard at concentrations ranging from 5 to 100 ppbv, focusing on calibration linearity, detection limits and reproducibility.

Methodology and Used Instrumentation

• Sampling: 200 ml/min for 5 min drawing from a Tedlar bag containing a 1 ppm 65-component standard.
• Sorbent tube: Standard six-inch multibed Tenax/Carboxen 1000/Carbosieve SIII tube.
• Thermal desorption: CDS TDA 9300 (valve oven 300 °C, transfer line 300 °C, dry purge 35 °C/1 min, tube heat 350 °C/5 min, trap idle 40 °C, trap heat 325 °C/5 min, tube cool 0.5 min).
• Gas chromatography: Varian CP 3800 with CP-Select 624 column (30 m×0.25 mm×1.4 µm), helium carrier gas.
• Detection: Varian Saturn 2000 Ion Trap mass spectrometer in full-scan mode.

Main Results and Discussion

Calibration curves for all 65 VOCs exhibited excellent linearity (R² > 0.999), with relative standard deviations below 8.4 %. Overlay chromatograms from 5 to 100 ppbv confirm consistent retention times and peak shapes for both light gases (e.g., dichlorodifluoromethane) and heavier aromatics (e.g., toluene).

Benefits and Practical Applications of the Method

The automated TO-17 workflow offers sensitive detection limits (0.5–2 ppb), robust reproducibility and high throughput, making it suitable for ambient air quality monitoring, industrial emission testing and regulatory compliance studies.

Future Trends and Potential Applications

Future developments may include integration of high-resolution mass spectrometry for isomer differentiation, novel sorbent materials for sub-ppb detection, portable field-deployable thermal desorption units and networked data platforms for real‐time air quality assessment.

Conclusion

The CDS TDA 9300 autosampler, combined with GC–ion trap analysis, provides a reliable and efficient solution for EPA TO-17 VOC monitoring, delivering outstanding linearity, sensitivity and precision across a broad concentration range.

References

• U.S. EPA Method TO-17: Determination of Volatile Organic Compounds in Ambient Air by Sorbent Tube Thermal Desorption.
• CDS Analytical Inc. Application Note #109: TO-17 Analysis using the CDS TDA 9300 Autosampler.