SICRIT® Technology for Fast and Direct SPME-MS Analysis of Environmental Trace Contaminants

Significance of the topic

The ability to rapidly and directly detect trace contaminants in environmental samples is critical for water quality monitoring, pollution assessment and regulatory compliance. Conventional LC-MS or GC-MS workflows require extensive sample preparation and chromatographic separation, creating bottlenecks in high-throughput screening. The direct coupling of solid-phase microextraction (SPME) with soft plasma ionization provides a streamlined alternative that can address both polar and non-polar analytes without lengthy pretreatment.

Aims and overview of the study

This application note evaluates a method integrating SPME with Plasmion’s SICRIT® dielectric barrier discharge ion source on an LTQ Orbitrap platform to achieve fast, sensitive and quantitative analysis of environmental trace contaminants. The main goals are:

• To demonstrate direct SPME-SICRIT-MS analysis without sample cleanup
• To assess performance across a polarity range of analytes
• To establish limits of detection, linearity and throughput for high-throughput screening

Used Instrumentation

The experimental setup comprised automated SPME sampling and SICRIT ionization:

• Autosampler: PAL RTC system (CTC Analytics)
• SPME device: DVB/PDMS arrow
• Extraction protocol: 5 min at 40 °C, stirring at 1 500 rpm
• Desorption: 1.5 min at 260 °C, split 1 : 10
• Ion source: SICRIT® soft ionization (1.5 kV, 10 kHz)
• Carrier gas: Humidified N₂ (90 % RH)
• Mass spectrometer: LTQ Orbitrap (Thermo Fisher)

Main results and discussion

The method was tested with polycyclic aromatic hydrocarbons (PAHs) in water, soil samples spiked with pesticides, and fruit matrices for insecticide detection:

• PAH analysis achieved ppt-level limits of detection, linear calibration curves (R² > 0.99) within an 8 min total run time
• Use of fluorobenzene dopant improved ionization efficiency, further lowering LODs
• Soil spiked with multiple pesticides was profiled in full-scan HRMS mode, demonstrating non-target screening capability
• In an apple matrix, sulfotep calibration yielded an LOD of 80 ng/L, confirming quantitative performance in complex food samples

Benefits and practical applications of the method

The direct SPME-SICRIT-MS workflow offers:

• Minimal preparation and rapid analysis suitable for high-throughput screening
• Soft ionization with limited fragmentation, preserving molecular ions
• Broad analyte coverage from polar to non-polar compounds
• Seamless integration with existing LC-MS instruments and autosamplers
• High-resolution data for confident compound identification

Future trends and opportunities

Ongoing developments are expected to include:

• Expanded non-target screening libraries enabled by HRMS coupling
• Optimized dopant strategies to further enhance sensitivity
• Miniaturized or portable SPME-plasma devices for in-field monitoring
• Automation of data processing pipelines for real-time decision support
• Validation across diverse environmental and food matrices

Conclusion

This study demonstrates that coupling SPME with SICRIT® soft ionization on an Orbitrap platform delivers a fast, sensitive and versatile solution for trace contaminant analysis. The approach reduces sample preparation time, extends detectability across a wide polarity range, and supports both targeted and non-targeted screening, making it a promising tool for environmental, food and forensic laboratories.

References

1. Mirabelli M.F., Wolf J.-C., Zenobi R. Anal. Chem. 2016, 88, 7752–7758.
2. Huba A.K., Mirabelli M.F., Zenobi R. Anal. Chim. Acta 2018, 1030, 125–132.