Solid Phase Microextraction (SPME) followed by HAPSITE ER Detection and Identification of Semi-Volatile Polychlorinated Hydrocarbons in an Aqueous Mixture

Significance of the Topic

The reliable detection of semi-volatile organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated hydrocarbons (PCHs) in water is critical for environmental monitoring and public health. Combining solid phase microextraction (SPME) with compact mass spectrometry enables rapid, solvent-free sampling and analysis, facilitating on-site screening of carcinogenic contaminants.

Objectives and Study Overview

This work demonstrates a method for extracting and identifying a range of PAHs, polychlorinated aromatic hydrocarbons (PCAHs), and polychlorinated hydrocarbons using SPME coupled to a portable HAPSITE ER gas chromatograph–mass spectrometer. A 50 ng/mL aqueous standard containing 17 target analytes was prepared, sampled, and analyzed to evaluate extraction efficiency and chromatographic separation.

Methodology and Instrumentation

The procedure involved:

• Sample preparation: 20 mL distilled water with 5 g NaCl in a 40 mL vial to create a 25% w/v salt matrix, spiked to 50 ppb per analyte.
• SPME extraction: PDMS-coated fiber conditioned and immersed in the salted water for 10 minutes.
• Desorption and analysis: Fiber introduced into a 250 °C desorption chamber of the HAPSITE ER sampling interface, followed by GC–MS run.
• Mass spectrometric detection: Scanning m/z 43–300 at 1 scan/s over a 10 min 40 s analysis.

Instrumentation Used

• HAPSITE ER portable GC–MS with universal SPME interface
• SPME fiber: Polydimethylsiloxane (PDMS) coating
• GC column: Rtx-1MS, 15 m × 0.25 mm × 1.0 µm
• Column temperature program: 60 °C (2 min hold), ramp 16 °C/min to 120 °C, ramp 24 °C/min to 200 °C (5.92 min hold)

Main Results and Discussion

All 17 target analytes were effectively extracted and separated within retention times ranging from ~5.3 to 13.2 minutes. The total ion chromatogram exhibited clear peak resolution for dichlorobenzenes, naphthalene derivatives, PAHs, and chlorinated compounds at low nanogram-per-milliliter levels. The salt matrix enhanced analyte recovery, while the portable system provided rapid on-site capability without solvent use.

Benefits and Practical Applications

• Solvent-free, field-deployable sampling reduces laboratory burden and environmental impact.
• Efficient extraction of semi-volatile pollutants from aqueous samples.
• Rapid screening for regulatory compliance and environmental assessment.

Future Trends and Applications

The approach may be extended by:

• Developing new fiber coatings for broader analyte coverage.
• Integrating automated sampling for unattended monitoring stations.
• Coupling to advanced data processing for real-time contaminant identification.
• Applying to other matrices such as soil pore water or industrial effluents.

Conclusion

The integration of SPME with the HAPSITE ER system offers a robust method for detecting and identifying semi-volatile hydrocarbon pollutants in aqueous environments. Its portability, sensitivity, and solvent-free workflow make it an attractive tool for environmental monitoring and rapid field analysis.