Semivolatile Organics on Rxi®-5Sil MS by U.S. EPA Method 8270

Significance of the Topic

Accurate identification and quantification of semivolatile organic compounds (SVOCs) is critical in environmental monitoring, industrial quality control and regulatory compliance. EPA Method 8270 remains a standard for analyzing a broad range of SVOCs in water, soil, and waste matrices. A column with minimal bleed, robust thermal stability and high resolution enhances the reliability and sensitivity of GC-MS analyses of these compounds.

Objectives and Study Overview

This study evaluates the performance of the Rxi®-5Sil MS GC column for separation and detection of 95 SVOCs, surrogates and internal standards following EPA Method 8270. The aim is to demonstrate chromatographic resolution, low bleed characteristics at high temperatures and suitability for complex environmental mixtures.

Methodology and Instrumentation

The analytical procedure employed pulse splitless injection of standard mixes spiked with isotopically labeled surrogates. A temperature program from 40 °C to 320 °C was used to elute low- to high-boiling SVOCs. Mass spectrometric detection was carried out in full scan mode across 35–550 amu.

Used Instrumentation

• GC: Agilent 7890A with pulsed splitless injection (1 µL, 30 psi, 0.64 min pulse).
• Column: Rxi®-5Sil MS, 30 m × 0.25 mm ID, 0.25 µm film thickness.
• Carrier gas: Helium at 1.2 mL/min constant flow (linear velocity 39.7 cm/s at 40 °C).
• MS: Agilent 5975C quadrupole, EI at 70 eV, source 276 °C, quad 150 °C, transfer line 280 °C, scan rate 5.36 scans/s.
• Temperature program: 40 °C (1 min) → 280 °C at 25 °C/min → 320 °C at 5 °C/min (1 min hold).

Main Results and Discussion

Separation of 95 target compounds, including numerous isomers and nitroaromatics, was achieved in under 17 minutes with distinct baseline resolution. The column exhibited extremely low bleed at 320 °C, ensuring minimal background noise and enhanced detection limits. Extracted ion chromatograms confirmed correct retention order for surrogates and internal standards, validating quantitation accuracy.

Benefits and Practical Applications

• High thermal stability and low bleed improve robustness for routine environmental monitoring.
• Broad analyte range covers phenols, nitroaromatics, PAHs, phthalates and more, meeting regulatory scope.
• Fast program ramps increase sample throughput in QA/QC laboratories.

Future Trends and Possibilities

Advances may include coupling with high-resolution MS for non-target screening, faster oven ramps for ultra-high throughput, and development of tailored stationary phases to further enhance separation of challenging isomeric SVOCs. Automation and miniaturization trends could enable on-site environmental screening.

Conclusion

The Rxi®-5Sil MS column provides reliable, high-resolution separation of a comprehensive suite of SVOCs under EPA Method 8270 conditions. Its low bleed and thermal robustness make it a valuable tool for environmental and industrial laboratories demanding accurate quantitation across diverse compound classes.

Reference

• U.S. EPA. Method 8270D: Semivolatile Organic Compounds by GC/MS. Washington, DC, 2014.
• Restek Corporation. Rxi®-5Sil MS GC Column Technical Data Sheet.