SPME Portable Field Sampler with 100μm PDMS Fiber

Significance of the Topic

The ability to perform solid phase microextraction (SPME) in the field using a portable sampler equipped with a 100 µm PDMS fiber addresses critical needs in environmental monitoring and pesticide analysis. This approach simplifies sample collection, minimizes losses of volatile and semivolatile compounds, and ensures analyte stability during transport to the laboratory for gas chromatographic analysis.

Study Objectives and Overview

This document outlines the design features, operational workflow, and performance metrics of the Supelco SPME Portable Field Sampler. Key goals include assessing analyte recovery after field storage on the fiber versus storage in water, evaluating sampler durability and reusability, and providing practical guidance for routine field deployment.

Methodology

Sampling and analysis follow several controlled steps:

• Fiber Conditioning: PDMS fiber is conditioned at 280 °C in the GC injection port for ≥30 min to remove impurities.
• Sample Preparation: Field samples (liquid or headspace) are prepared in septum-capped vials, agitated, and heated if required.
• Extraction: The fiber is exposed to the sample or headspace for a defined period, with depth controlled by the needle guide slots.
• Storage: After extraction, the fiber retracts into the protective needle; analytes can be stored for up to 3 days at ambient temperature with minimal loss, or longer at subambient conditions.
• Desorption: In the laboratory, the fiber is inserted into the GC injection port at a consistent depth and time to thermally desorb analytes.

Instrumentation Used

• Supelco SPME Portable Field Sampler with lockable plunger and depth-adjusting needle guide.
• 100 µm PDMS (polydimethylsiloxane) fiber.
• Aluminum nosepiece with replaceable Thermogreen LB-2 sealing septum.
• Gas chromatograph equipped with a suitable injection port liner and temperature control.

Main Results and Discussion

Comparative storage tests demonstrated that pesticides extracted and held on the PDMS fiber experienced an average loss of ~8 % after 24 h at 4 °C, versus ~75 % loss when stored in water vials under the same conditions. Individual compounds such as atrazine, DDE, and methoxychlor showed significantly higher retention on the fiber. The durable polymer body and replaceable septum maintained sample integrity, and fiber life exceeded 50–100 extraction/desorption cycles.

Benefits and Practical Applications

Key advantages include:

• Enhanced analyte retention during storage and transport.
• Rapid sampling without solvents or extensive preparation.
• Reusability of fibers for cost-effective operation.
• Compatibility with headspace and direct-liquid sampling.
• Reliable depth control for reproducible desorption in GC analyses.

This method is applicable in environmental field surveys, pesticide residue monitoring, QA/QC laboratories, and industrial process control.

Future Trends and Opportunities

Advancements may focus on novel fiber coatings to expand analyte range, integration of miniaturized field-deployable GC systems for on-site analysis, automated depth and time control for improved reproducibility, and enhanced cold-storage accessories to extend analyte stability over longer periods.

Conclusion

The Supelco SPME Portable Field Sampler with 100 µm PDMS fiber offers an effective, user-friendly solution for field sampling of volatile and semivolatile compounds. Its robust design, high analyte retention, and simple operation make it a valuable tool for diverse analytical applications requiring reliable field-to-laboratory workflows.

References

• Supelco. SPME Portable Field Sampler with 100 µm PDMS Fiber: Product Specification, Sigma-Aldrich Co., 1997.