TO-15 65 Component Mix on Rxi®-624Sil MS (30 m)

Significance of the Topic

Volatile organic compound analysis by gas chromatography–mass spectrometry is a cornerstone in environmental monitoring and regulatory compliance, offering sensitive detection of trace-level pollutants in air, water, and soil matrices.

Objectives and Study Overview

This application assesses the performance of an Rxi-624Sil MS column in separating a standard TO-15 mix of 65 volatile compounds. The study focuses on retention behavior, resolution, and analysis time required to achieve complete chromatographic separation.

Methodology

The workflow involved direct injection of a 200 mL, 10 ppbv TO-15 standard into a cryofocus preconcentrator, followed by GC–MS analysis under the following key conditions:

• Preconcentration on Nutech 8900DS with dual traps: glass beads (Trap 1) and Tenax® (Trap 2).
• Cryofocusing temperatures ranging from –160 °C to –20 °C for efficient analyte focusing.
• Oven program: 32 °C hold 1 min, ramp at 11 °C/min to 150 °C, then 33 °C/min to 230 °C.
• Helium carrier gas at 2.0 mL/min constant flow, linear velocity 51 cm/s at 32 °C.

Used Instrumentation

• Gas chromatograph: Agilent HP 6890 GC with Rxi®-624Sil MS column (30 m × 0.32 mm ID, 1.80 μm film).
• Mass spectrometer: Agilent 5973 MSD, electron ionization at 69.9 eV, scan range 35–250 amu at 3.32 scans/s.
• Preconcentrator: Nutech 8900DS with specified desorption and bakeout parameters.

Main Results and Discussion

The optimized method achieved baseline separation of all 65 target analytes, including halogenated hydrocarbons, aromatic compounds, ketones, alcohols, and ethers, within a total runtime of 13.7 minutes. Retention times aligned with compound volatility and polarity, delivering sharp, symmetric peaks and reliable mass calibration via a tuning standard.

Benefits and Practical Applications

This approach provides high throughput and robust quantitation of trace-level volatiles for environmental laboratories, offering:

• Rapid analysis with complete resolution of a complex mixture.
• Sensitivity suitable for low ppbv-level detection.
• Compliance with EPA TO-15 and similar regulatory protocols.

Future Trends and Applications

Emerging directions include:

1. Integration of high-resolution mass spectrometry to enhance selectivity and identification confidence.
2. Development of advanced sorbent materials for broader analyte capture and reduced breakthrough.
3. Automation of sample introduction and data processing for increased laboratory productivity.

Conclusion

The presented GC–MS method, combining cryogenic preconcentration with an Rxi-624Sil MS column, delivers a rapid, sensitive, and reliable platform for comprehensive TO-15 volatile analysis, suited for diverse environmental and industrial applications.

References

No external references were provided.