Air Sampling of VOCs Using New SPME Portable Field Sampler

Importance of the Topic

The accurate monitoring of volatile organic compounds (VOCs) in air is critical for environmental safety, workplace health, and regulatory compliance. Traditional sampling methods often require bulky equipment, sample transport, and immediate laboratory analysis, increasing cost and risk of analyte loss. The development of a portable solid phase microextraction (SPME) field sampler paired with a Carboxen™/PDMS fiber addresses these challenges by enabling on-site trapping, preservation, and later laboratory analysis of trace VOCs.

Objectives and Overview

This study introduces two new products for field VOC analysis: a handheld SPME sampler and a high-capacity Carboxen/PDMS fiber. The goals were to demonstrate (1) efficient extraction of low-level VOCs directly in air without transport loss, (2) retention of analyte integrity during delayed laboratory desorption, and (3) linear response across trace concentration ranges for key industrial pollutants.

Methodology and Instrumentation

The portable sampler is a self-sealing needle device that houses the SPME fiber behind a septum, preventing analyte loss during transport. The fiber is coated with 75 µm Carboxen/PDMS, exploiting Carboxen’s porous matrix for high adsorption of VOCs.

• Sampling: 10 min headspace extraction from a 125 mL bulb spiked with nine VOCs (400 ppt–400 ppb).
• Desorption: 5 min at 300 °C in a splitless GC inlet.
• Chromatography: SPB™-1 SULFUR capillary column (30 m × 0.32 mm, 4.0 µm) with helium carrier (35 cm/s).
• Detection: GC/MS ion trap scan m/z 45–260.

Main Results and Discussion

All nine target VOCs yielded strong signals at 10 ppb (Figure A). Calibration curves over 0.4–400 ppb showed excellent linearity (R2 ≥ 0.98 for eight compounds; R2 = 0.953 for 1,2-dichloroethane). Contrary to expectations that heavy analytes might displace lighter ones at higher loadings, the Carboxen structure maintained equal retention capacity without competition effects.

Benefits and Practical Applications

The combined sampler and fiber enable:

• On-site sampling with negligible analyte loss.
• Delayed laboratory analysis without degradation.
• Trace-level quantitation of a broad range of VOCs in environmental and industrial settings.

Future Trends and Potential Applications

Further miniaturization and integration with portable GC/MS units could allow fully field-deployable analytical platforms. Modification of fiber coatings may extend this approach to semi-volatile organics and emerging pollutants. Combination with real-time wireless reporting will enhance rapid decision-making for environmental emergencies and compliance monitoring.

Conclusion

The new SPME portable field sampler and Carboxen/PDMS fiber deliver a robust, user-friendly solution for trace VOC air monitoring. Their high adsorption capacity, transport security, and linear performance simplify field sampling workflows and improve data reliability.

Reference

Shirey R., Mani V., Betz W. Air Sampling of VOCs Using New SPME Portable Field Sampler. Supelco Reporter. Vol. 16, No. 4, 1997.