Determination of Volatile Organic Compounds in Soils By HS-GC/MS

Importance of the Topic

Volatile organic compounds (VOCs) in soil pose significant risks to human health and the environment due to their toxicity, persistence and potential carcinogenicity. Monitoring trace levels of VOCs is essential for regulatory compliance, risk assessment and remediation strategies in environmental and industrial settings.

Study Objectives and Overview

This study aimed to demonstrate and validate a headspace gas chromatography/mass spectrometry (HS-GC/MS) procedure for the determination of thirty-six priority VOCs in soil. The method follows US EPA method 5021/8260 and China’s HJ642-2013 standard, using PerkinElmer TurboMatrix™ HS40 coupled to Clarus® SQ 8 GC/MS. Performance parameters including linearity, precision, detection limits and recovery were evaluated to verify compliance with regulatory criteria.

Methodology and Instrumentation

Soil samples were prepared by adding 2.0 g quartz sand, 5.0 mL of matrix-modifying solution (pH 2, 180 g NaCl in reagent water) and appropriate volumes of calibration, internal and surrogate standards to 22 mL headspace vials. The headspace sampler was operated at 70 °C with a 50 min equilibration, 30 psi vial pressurization and 0.05 min injection. GC separation used a 60 m × 0.32 mm × 1.8 µm Elite-624 capillary column with a split ratio of 20:1. Oven programming started at 35 °C, ramped to 120 °C (4 °C/min), 180 °C (8 °C/min) and 220 °C (15 °C/min) with hold times to optimize resolution of low-boiling VOCs. MS detection in electron ionization mode used selected ion monitoring (SIM) after a 3 min solvent delay.

Main Results and Discussion

The method achieved excellent chromatographic resolution for all thirty-six compounds, with higher peak areas observed using 5 mL of modifier vs 10 mL, particularly for polar analytes. Calibration curves yielded r² values above 0.995 for all targets. Precision (RSD) was below 8.8% at 100 and 250 µg/kg levels. Method detection limits (MDLs) ranged from 0.54 to 1.24 µg/kg and method quantitation limits (MQLs) from 2.17 to 6.14 µg/kg. Recoveries fell within 75–117%, meeting or exceeding both EPA and HJ642-2013 requirements. Reduced modifier volume cut costs and waste while maintaining regulatory compliance.

Benefits and Practical Applications of the Method

• Full compliance with US EPA 5021/8260 and China HJ642-2013 performance criteria.
• High sensitivity and reproducibility for trace-level VOCs in soil matrices.
• Optimized solvent use reduces cost, handling time and laboratory waste.
• Adaptable workflow for environmental monitoring, site assessment and quality control.

Future Trends and Potential Applications

Advances may include automated sample handling, integration with ambient screening devices and high-throughput platforms. Coupling HS-GC/MS with machine learning for data interpretation can accelerate compound identification. Miniaturized or portable headspace analyzers could enable on-site VOC monitoring. Expanding the method to emerging contaminants and non-targeted screening will enhance environmental risk management.

Conclusion

The PerkinElmer TurboMatrix HS40-Clarus SQ 8 GC/MS configuration provides a robust, cost-effective and compliant solution for quantifying thirty-six VOCs in soil. The method demonstrates superior sensitivity, precision and recovery, meeting stringent EPA and Chinese regulatory standards while minimizing solvent use and waste.

Used Instrumentation

• PerkinElmer TurboMatrix HS40 Headspace Sampler
• PerkinElmer Clarus SQ 8 GC/MS
• Elite-624 GC Column (60 m × 0.32 mm × 1.8 µm)

References

1. Method 5021, Volatile organic compounds in soils and other solid matrices using equilibrium headspace analysis, US EPA.
2. HJ642-2013, Soil and sediment—Determination of volatile organic compounds—Headspace-gas chromatography/mass spectrometry method, China’s Ministry of Environmental Protection.