Semivolatiles on Rtx®-5 with 5 m Integra-Guard® by EPA Method 8270

Significance of the Topic

Accurate detection and quantification of semivolatile organic compounds is crucial for environmental monitoring, compliance with regulatory standards, and quality assurance in industrial processes. Method 8270 provides a robust framework for identifying a broad range of semivolatiles in soil, water, and air matrices, supporting risk assessment and pollution control efforts.

Objectives and Study Overview

This study evaluates the performance of a 30 m Rtx-5 column equipped with a 5 m Integra-Guard guard column using EPA Method 8270. Key aims include demonstrating compound resolution, retention time reproducibility, and sensitivity across 144 target analytes ranging from small nitrosamines to high-molecular-weight polycyclic aromatic hydrocarbons.

Methodology

• Sample mixes included an internal standard suite, surrogate standards, and an 8270 MegaMix of target compounds.
• Injection used pulsed splitless mode at 270 °C with a 0.7 min hold and 0.8 min pulse time.
• Oven temperature program started at 40 °C, ramped to 90 °C at 12.5 °C/min, followed by defined ramps to 246 °C and 325 °C with holds for elution of late-eluting analytes.
• MS detection operated in full scan mode (35–550 amu) at 5.6 scans/sec, electron ionization at 70 eV.

Instrumentation

• Gas chromatograph Agilent 7890A with 30 m Rtx-5 column (0.25 mm ID, 0.50 µm) plus 5 m Integra-Guard guard column.
• Mass spectrometer Agilent 5975C in scan mode with inert source and quadrupole analyzer.
• Carrier gas helium at 2.08 mL/min constant flow.
• Transfer line temperature 320 °C, source temperature 350 °C, quadrupole at 180 °C.

Main Results and Discussion

The method resolved all 144 semivolatiles with baseline or near-baseline separation. Early eluters such as nitrosamines and low-molecular seeds appeared before 6 min, while heavy PAHs eluted beyond 20 min. Mass spectral ion traces at m/z 93, 139, 184, and 252 enabled selective monitoring of key compound classes. Peak shapes and retention times were highly reproducible, supporting repeatable quantitation across multiple runs.

Benefits and Practical Applications

• Comprehensive coverage of nitrosamines, phenols, nitrophenols, phthalates, chlorinated pesticides, and PAHs in a single run.
• High sensitivity and selectivity for trace-level environmental contaminants.
• Reduced maintenance through use of an inline Integra-Guard guard column to protect the analytical column.
• Applicability to regulatory compliance testing in environmental laboratories and industrial QA/QC.

Future Trends and Potential Uses

Further integration of high-resolution MS and tandem MS detection may enhance identification of emerging contaminants. Miniaturized and automated sampling interfaces, coupled with faster temperature programs, can reduce analysis time. Adapting Method 8270 workflows to GCxGC and time-of-flight MS platforms will support broader screening of non-target semivolatiles.

Conclusion

The Rtx-5 column with 5 m Integra-Guard demonstrates reliable performance for EPA Method 8270 semivolatile analysis. It achieves robust separation, consistent retention times, and high sensitivity for a diverse set of 144 compounds, making it an effective solution for environmental and industrial laboratories seeking compliance and operational efficiency.