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

Significance of the Topic

The growing need for rapid and robust trace contaminant analysis in environmental, food, and forensic contexts has driven the development of ambient mass spectrometry approaches. Direct coupling of solid-phase microextraction (SPME) with a soft ionization source offers a streamlined workflow that bypasses lengthy chromatographic separation and extensive sample preparation.

Study Objectives and Overview

This work demonstrates a versatile, high-throughput screening method that combines SPME arrow extraction with Plasmion’s SICRIT® dielectric barrier discharge ion source and high-resolution mass spectrometry. Specific aims include:

• Evaluating sensitivity and linearity for both polar and non-polar analytes in water matrices
• Demonstrating non-target pesticide screening in spiked soil samples
• Quantifying insecticide residues in fruit matrices
• Assessing compatibility with automatic sampling for fast routine analysis

Methodology and Instrumentation Used

Experiments were performed on an LTQ Orbitrap mass spectrometer fitted with a SICRIT® plasma ionization device operated at 1.5 kV and 10 kHz.

• Autosampler: PAL RTC system for automated SPME arrow handling
• SPME arrow: DVB/PDMS phase, extraction at 40 °C, 1500 rpm for 5 min
• Desorption: 260 °C for 1.5 min directly into the ion source
• Carrier gas: humidified nitrogen (90 % relative humidity)
• Dopant addition (e.g., fluorobenzene) to enhance ionization efficiency of non-polar compounds

Main Results and Discussion

Direct SPME-SICRIT®-MS achieved excellent linearity (R² > 0.99) and limits of detection in the low ppt range for polycyclic aromatic hydrocarbons (PAHs) and various environmental standards. Incorporation of dopants significantly improved signal intensity for low-polarity analytes. High-resolution full-scan MS enabled reliable non-target screening of pesticides spiked into soil. In food-matrix trials, sulfotep calibration in apple juice reached an LOD of 80 ng/L, illustrating quantitation capability in complex matrices.

The soft ionization regime minimized fragmentation, extending detectable analyte range and facilitating identification of labile compounds without chromatography.

Benefits and Practical Applications

This approach offers:

• Fast sample throughput with total run times around 8 minutes
• Elimination of labor-intensive pretreatment and separation steps
• Broad analyte polarity coverage in a single measurement
• Seamless integration with existing LC-MS platforms
• Automated workflow for reproducible high-throughput screening

Future Trends and Potential Applications

Anticipated developments include:

• Expanded use of non-target screening in environmental monitoring and forensic casework
• On-site or field-deployable MS systems with integrated SPME-SICRIT modules
• Novel dopant chemistries to further boost sensitivity for ultra-low polarity residues
• Coupling with advanced data-analysis tools and machine learning for rapid contaminant profiling

Conclusions

The direct SPME-SICRIT®-MS workflow provides a rapid, sensitive, and versatile platform for trace contaminant analysis across environmental, food, and forensic applications. Its minimal sample handling, broad analyte compatibility, and compatibility with high-resolution MS establish it as a promising high-throughput screening technology.

References

1. Mirabelli M.F., Wolf J.-C., Zenobi R. Analytical Chemistry 2016, 88, 7752–7758.
2. Huba A.K., Mirabelli M.F., Zenobi R. Analytica Chimica Acta 2018, 1030, 125–132.