Volatile Organic Compound Screening in Soil Using SPME-GC/MS

Význam tématu

The ability to perform rapid, on-site screening of volatile organic compounds (VOCs) in soils is critical for environmental monitoring, risk assessment and real-time decision making during field investigations.

Cíle a přehled studie

This application note evaluates a portable solid phase microextraction (SPME) coupled to a compact gas chromatograph/mass spectrometer (GC/MS) system for in-field VOC analysis in soil. The main objective was to demonstrate positive identification of multiple target VOCs and estimate their relative concentrations within minutes, following U.S. EPA guidelines for near-real-time screening.

Použitá instrumentace

The field workflow employed a Custodion SPME syringe fitted with a 65 µm PDMS/DVB fiber to extract VOCs from saline water-treated soil headspace. Desorption and separation were achieved with a Torion T-9 portable GC/MS using:

• MXT-5 capillary column (5 m × 0.1 mm, 0.4 µm film)
• Helium carrier gas at constant flow (0.2 mL/min)
• Injector temperature of 250 °C and a temperature program from 40 °C to 280 °C at 2 °C/s (total run under 2.5 min)
• Toroidal ion trap mass analyzer (mass range 41–500 Da, ∼10 Hz scan rate) with in-trap electron impact ionization and electron multiplier detection

Hlavní výsledky a diskuse

In a spiked reference soil sample containing 42 VOCs (2.4–15 ppm w/w), 37 compounds were positively identified in under two minutes. Co-elution of several analytes was resolved by on-board spectral deconvolution and a custom target library. Five highly volatile compounds were not detected, likely due to losses during extraction or selective fiber discrimination. Overall method precision and speed support effective field screening.

Přínosy a praktické využití metody

This portable SPME-GC/MS approach eliminates the need for solvents and laboratory infrastructure, reducing sampling costs and turnaround times. On-site positive identification of individual VOCs guides further sampling strategies and minimizes expensive re-analysis and instrument downtime due to carryover.

Budoucí trendy a možnosti využití

Future developments may include advanced SPME coatings for broader analyte coverage, integration of automated data processing and cloud-based reporting, and expanded target libraries for emerging contaminants. Continued miniaturization and battery operation will further enhance in-field capabilities.

Závěr

The combination of Custodion SPME sampling and Torion T-9 GC/MS detection provides a robust, rapid and portable solution for VOC screening in soil. Its ease of use and fast turnaround support informed decision making during environmental field investigations.

Reference

1. EPA SW-846 Method 3815 Screening Solid Samples for Volatile Organics, Revision 0, February 2007.
2. Zhang Z.; Pawliszyn J. Analysis for organic compounds in environmental samples by headspace solid phase microextraction. Journal of High Resolution Chromatography. 1993, 16(12), 689-692.