Semivolatiles With Appendix IX on Rxi®-5ms by 8270D

Significance of the Topic

Semivolatile organic compounds encompass a wide range of environmental and industrial contaminants including nitrosamines, phenols, polyaromatic hydrocarbons (PAHs), phthalates and pesticides. Reliable quantification of these analytes at trace levels is critical for assessing human exposure, environmental monitoring and regulatory compliance. The Appendix IX method on a high-performance GC/MS platform offers a comprehensive approach to screen and quantify over 140 semivolatiles in complex matrices.

Study Objectives and Overview

This application note describes the development and validation of a gas chromatography-mass spectrometry (GC/MS) method for semivolatiles according to Appendix IX guidance using an Rxi®-5ms capillary column. The aim is to achieve robust separation, reproducible retention times and sensitive detection in scan mode. A mixed standard containing internal standards, surrogates and target analytes was used to evaluate method performance over a broad chemical range.

Methodology

Sample Preparation and Standards

• Dissolution of analyte mix in dichloromethane with internal standards (10 µg/mL for analytes; 20 µg/mL for internal standards).
• Injection: 1 µL split (10:1) into GC inlet at 275 °C with a 4 mm wool-packed liner.

Chromatographic Conditions

• Column: Rxi®-5ms, 30 m × 0.25 mm ID, 0.25 µm film thickness.
• Carrier gas: Helium, 1.44 mL/min constant flow.
• Oven program: 50 °C (0.5 min), to 265 °C at 28 °C/min, to 285 °C at 3 °C/min, to 330 °C at 25 °C/min (1 min hold).

Mass Spectrometry

• Detector: Quadrupole MS in scan mode (35–550 amu).
• Transfer line: 290 °C; ion source: 330 °C; quadrupole: 180 °C.
• Ionization: 70 eV EI; tune type: DFTPP; solvent delay 1.35 min.

Instrumentation Used

The analysis was performed on an Agilent 7890A gas chromatograph coupled to an Agilent 5975C mass selective detector. The Rxi®-5ms column provided low bleed and high inertness, essential for semivolatile analysis.

Main Results and Discussion

The method successfully resolved a mixture of 144 semivolatile compounds spanning polar nitrosamines to high-molecular-weight PAHs. Retention times were reproducible (< 0.1 min RSD) and peak shapes were sharp across the temperature program. Scan-based detection allowed broad coverage, while extracted ion chromatograms for key m/z values improved sensitivity for low-abundance analytes. Method performance met Appendix IX criteria for linearity, precision and accuracy.

Benefits and Practical Applications

This GC/MS method provides laboratories with a unified workflow for semivolatiles, minimizing the need for multiple specialized assays. It is suitable for:

• Environmental water, soil and sediment monitoring.
• Industrial wastewater and process QC.
• Public health exposure assessments.

Future Trends and Potential Applications

Advancements in high-resolution MS and two-dimensional GC could further enhance selectivity and confidence in compound identification. Coupling with automated sample preparation and data-processing software may streamline large-scale monitoring programs. Emerging applications include suspect screening of novel semivolatiles and retrospective data mining.

Conclusion

The Appendix IX semivolatiles method on an Rxi®-5ms GC/MS platform delivers comprehensive coverage, robust performance and practical throughput. It meets regulatory requirements for trace-level analysis and supports a wide range of environmental and industrial testing needs.

References

No external references were cited in the original document.