Semivolatiles on Rxi-5Sil MS by U.S. EPA Method 8270 Using the GC Accelerator Kit and Split Injection with a 120 V GC Oven

Importance of the Topic

Semivolatile organic compounds represent a diverse class of environmental pollutants, including nitrosamines, phenols, phthalates, chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. Reliable identification and quantification of these analytes is critical for environmental monitoring, regulatory compliance and public health risk assessment. The development of rapid, robust gas chromatography–mass spectrometry (GC-MS) methods enhances laboratory throughput and analytical confidence.

Objectives and Study Overview

This application examines U.S. EPA Method 8270 for semivolatiles using a Restek Rxi-5Sil MS column in conjunction with an Agilent GC equipped with the GC Accelerator Kit and a 120 V oven. The goal is to achieve baseline separation of 94 target compounds in a single 10.6-minute run, demonstrating high resolution, peak symmetry and method ruggedness under split injection conditions.

Methodology

The study employed a 20 m × 0.15 mm ID Rxi-5Sil MS column with 0.15 µm film thickness. A 1 µL aliquot of a 20 µg/mL semivolatile mix, surrogates and internal standards in methylene chloride was injected in split mode (20:1). The oven program initiated at 60 °C (0.7 min hold), ramped to 285 °C at 39.8 °C/min, then to 305 °C at 4.3 °C/min and finally to 330 °C at 28.5 °C/min, with a 3.5 min final hold. Helium carrier gas was maintained at 0.72 mL/min constant flow.

Instrumentation

• Gas chromatograph: Agilent 7890B with GC Accelerator Kit (120 V oven)
• Mass spectrometer: Agilent 5977A MSD, quadrupole analyzer, EI mode (70 eV)
• Column: Restek Rxi-5Sil MS, 20 m × 0.15 mm ID, 0.15 µm film
• Liner: Topaz 4 mm single taper with wool
• Transfer line temperature: 280 °C; source: 330 °C; quadrupole: 180 °C
• Scan range: m/z 39–550 at 9.8 scans/sec; solvent delay 1.3 min

Main Results and Discussion

The optimized method resolved 94 semivolatile targets with retention times spanning 1.40 to 10.63 minutes. Valley values for critical peak pairs exceeded 60–90%, indicating excellent chromatographic resolution. Early eluters included 1,4-Dioxane-d8 (IS) and N-Nitrosodimethylamine, while late eluters featured high-molecular-weight PAHs such as benzo[ghi]perylene. The accelerated oven performance reduced total analysis time by over 50% compared to conventional heating profiles. Peak shapes remained sharp and symmetrical, demonstrating minimal column bleed and robust temperature control.

Benefits and Practical Applications

• High-throughput analysis: single-run profiling of nearly 100 semivolatiles in ~10.6 min
• Regulatory compliance: meets or exceeds EPA 8270 performance criteria
• Laboratory efficiency: reduced oven cool-down time and solvent usage
• Data quality: consistent retention times, peak symmetry and sensitivity for diverse analytes

Future Trends and Opportunities

Advancements in fast GC technologies, ultra-low-bleed stationary phases and high-resolution mass spectrometry promise further reductions in analysis time and enhancements in selectivity. Integration with automated sample preparation and data processing workflows will support remote monitoring and on-site environmental testing. Emerging applications include forensic analysis of complex matrices and rapid screening for industrial process control.

Conclusion

The combination of EPA Method 8270, a Restek Rxi-5Sil MS column and an Agilent GC Accelerator Kit with a 120 V oven delivers rapid, high-resolution analysis of semivolatile organic compounds. This approach offers significant gains in throughput and data quality, supporting diverse environmental and industrial applications.

Reference

Restek Corporation. Semivolatiles on Rxi-5Sil MS by U.S. EPA Method 8270 Using the GC Accelerator Kit and Split Injection with a 120 V GC Oven (2017).