Semivolatiles on Rxi-5Sil MS by U.S. EPA Method 8270 Using the GC Accelerator Kit and Split Injection with a 208 V GC Oven

Significance of the topic

Analysis of semivolatile organic compounds is critical in environmental monitoring, industrial quality control and regulatory compliance. U.S. EPA Method 8270 remains a cornerstone for the detection and quantification of a broad range of semivolatiles, including phenols, nitroaromatics, phthalates and polycyclic aromatic hydrocarbons (PAHs). Enhancing throughput and resolution of this method directly supports faster decision-making and improved laboratory efficiency.

Objectives and study overview

This application note demonstrates the performance of the Rxi-5Sil MS capillary GC column coupled with Agilent’s GC Accelerator kit (208 V oven) for EPA Method 8270 analysis. The study aimed to:

• Validate separation of 94 target analytes and internal standards within a compressed run time.
• Assess resolution metrics (valley values and transfer functions) under split injection conditions.
• Illustrate method robustness for routine semivolatile screening.

Methodology

Standards and sample mixes representing the 8270 MegaMix, benzidine mix, acid surrogates and other target compounds were prepared at 20 µg/mL in methylene chloride. A 1 µL split injection (20:1) delivered analytes onto a 20 m × 0.15 mm ID, 0.15 µm Rxi-5Sil MS column. The oven program began at 45 °C (0.5 min hold), ramped to 285 °C at 56.5 °C/min, then to 305 °C at 6 °C/min and finally to 330 °C at 60.5 °C/min (2.5 min hold). Data acquisition employed full scan mass spectrometry (39–550 amu) at ~9.8 scans/sec.

Used instrumentation

• Gas Chromatograph: Agilent 7890B with GC Accelerator kit (208 V oven)
• Mass Spectrometer: Agilent 5977A MSD, quadrupole analyzer, EI ionization (70 eV)
• Column: Rxi-5Sil MS, 20 m × 0.15 mm ID, 0.15 µm film (Restek #43816)
• Carrier gas: Helium constant flow at 1.0 mL/min
• Injection liner: Topaz 4 mm single taper with wool (Restek #23303)
• Temperatures: Injector 275 °C; Transfer line 280 °C; Source 330 °C; Quadrupole 180 °C
• Scan parameters: Solvent delay 1.3 min; tune type DFTPP; scan rate 9.8 scans/sec

Main results and discussion

The compressed method achieved separation of 94 semivolatile analytes and deuterated/internal standards in under 8.5 minutes. Valley values above 46 % and transfer function near unity confirmed baseline resolution for critical pairs. Key observations included:

• Sharp peaks for early eluters such as nitrosamines and phenols (tR 1.3–2.5 min).
• High retention and resolution of PAHs and phthalates in the mid- to late-run (tR 3.6–6.7 min).
• Consistent detector response across a broad volatility range, demonstrating linearity and reproducibility.

Benefits and practical applications

The optimized configuration offers:

• High sample throughput by reducing cycle time.
• Robust separation for regulatory and forensic analyses.
• Compatibility with existing EPA 8270 protocols and QA/QC workflows.
• Reduced gas and energy consumption via the GC Accelerator kit.

Future trends and potential uses

Advances in GC column technology and oven engineering will further shorten analysis times and enhance resolution. Emerging areas include:

• Integration with high-resolution MS for improved selectivity.
• Automated sample handling and real-time data processing.
• Application to non-target screening in complex matrices.

Conclusion

The combination of the Rxi-5Sil MS column with Agilent’s GC Accelerator kit and a 208 V oven provides a rapid, reliable and EPA-compliant solution for semivolatile analysis under Method 8270. This approach enhances laboratory efficiency while maintaining high resolution and sensitivity across a wide compound range.

References

• U.S. EPA. Method 8270D: Semivolatiles by Gas Chromatography/Mass Spectrometry. EPA-821-R-02-019, 2007.
• Restek Corporation. Semivolatiles on Rxi-5Sil MS by U.S. EPA Method 8270 Using the GC Accelerator Kit and Split Injection with a 208 V GC Oven. Application Note, 2017.