Solid Phase Microextraction: Rapid and Versatile Extraction for GC or HPLC Applications

Significance of the Topic

Solid phase microextraction (SPME) offers a rapid, solvent-free approach to sample preparation that reduces environmental impact, lowers costs, and enhances sensitivity for trace-level analyses. By integrating directly with gas and liquid chromatography systems, SPME streamlines workflows in environmental monitoring, forensic toxicology, pharmaceutical research, and chemical ecology.

Objectives and Overview of the Article

This article reviews the principles of SPME and illustrates its versatility through four representative applications: analysis of polycyclic aromatic hydrocarbons (PAHs) in water by SPME/HPLC, monitoring of BTEX compounds in air by SPME/GC, detection of cocaine in urine via SPME/GC-NPD, and sampling of bio-volatiles in chemical ecology studies.

Methodology

SPME relies on a fused-silica fiber coated with stationary phases such as polydimethylsiloxane (PDMS) or polyacrylate. Depending on analyte polarity and volatility, fibers are exposed either directly to aqueous or liquid matrices (immersion mode) or to the headspace above samples. After adsorption, analytes are thermally desorbed into a heated GC injector or transferred via an interface to HPLC systems for chromatographic separation.

Used Instrumentation

• SPME fiber assemblies: 100 µm PDMS for volatiles, 7 µm PDMS for semivolatiles, 85 µm polyacrylate for polar compounds.
• SPME holders and autosampler-compatible modules for manual or automated sampling.
• SPME/HPLC interface compatible with Valco and Rheodyne valves.
• GC columns: SUPELCOWAX 10, SPB-1, SPB-5; Carbowax-type columns for BTEX analysis.
• HPLC column: SUPELCOSIL LC-PAH (15 cm × 4.6 mm, 5 µm).
• Detectors: flame ionization (FID), nitrogen-phosphorus (NPD), electron-impact ionization (EID), UV (254 nm).

Main Results and Discussion

• PAHs in Water: Using a 100 µm PDMS fiber and SUPELCOSIL LC-PAH column with an acetonitrile–water gradient, SPME/HPLC yielded sharp, symmetric peaks and up to ten-fold sensitivity gains at 1–2 ppb levels.
• BTEX in Air: Exposure of 100 µm PDMS fibers in 1–10 L sampling bags followed by GC analysis on a Carbowax-type column increased response ratios from 1.2× (benzene) to 14.6× (o-xylene) over 0.5 mL direct injections, with relative standard deviations below 5%.
• Cocaine in Urine: Immersion of PDMS fibers in spiked urine (250 ng each) for 30 min followed by GC–NPD detection achieved recoveries of 20–30%, linearity from 30–250 ng/0.5 mL, and a detection limit ~6 ng/0.5 mL, with minimal matrix interference.
• Chemical Ecology Sampling: Headspace SPME captured pheromones from single insects (leaf miner moths) and volatile emissions from wounded spruce seedlings, revealing distinct profiles of mono- and sesquiterpenes emitted upon damage.

Benefits and Practical Applications

SPME provides rapid, solventless extraction, reduces sample handling and waste, improves environmental compliance, and lowers detection limits. It simplifies workflows in environmental analysis (water and air monitoring), forensic toxicology, pharmaceutical screening, and ecological studies of volatile signaling.

Future Trends and Potential Applications

Advances in fiber coatings will extend SPME to a broader range of analytes, including highly polar and high-molecular-weight compounds. Integration with automated autosamplers, tandem mass spectrometry, and multidimensional separations will further enhance throughput and selectivity. Field-deployable SPME sensors promise in situ monitoring of contaminants and bioactive volatiles.

Conclusion

Solid phase microextraction has emerged as a versatile, efficient alternative to conventional extraction methods. Its compatibility with GC and HPLC, combined with reduced solvent use and improved sensitivity, positions SPME as a valuable tool across diverse analytical disciplines.

References

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