Analysis of advanced materials by FD/FI using “AccuTOF GC” - analysis of polymer building blocks with isocyanate and pilazole groups

Significance of the Topic

The analysis of reactive functional monomers, such as those bearing isocyanate and pyrazole groups, is critical for the development and quality control of advanced polymers. Accurate identification of molecular ions aids in structural confirmation and purity assessment, supporting industrial applications in coatings, adhesives and specialty materials.

Objectives and Study Overview

This study compares two ionization techniques—electron ionization (EI) and field ionization (FI)—coupled to a time-of-flight gas chromatography system (AccuTOF GC). Four functional monomers (AOI®, MOI®, BEI®, MOI-BP®) were evaluated to determine which method yields more reliable molecular‐ion detection for highly reactive compounds.

Methodology

Samples

• Chemical monomers from SHOWA DENKO K.K.: Karenz AOI® (C6H7NO3), MOI® (C7H9NO3), BEI® (C11H13NO5), MOI-BP® (C12H17N3O3).

GC Conditions

• Column: ZB-5ms, 30 m × 0.25 mm, 0.25 μm film
• Carrier gas: He at 1.0 mL/min (constant flow)
• Oven program: 40 °C (2 min) → 30 °C/min → 280 °C (12 min)

Instrumental Setup

Mass Spectrometry

• Instrument: JMS-T100GC AccuTOF GC (JEOL Ltd.)
• Acquisition range: m/z 35–550, scan interval 0.4 s
• EI conditions: 70 eV electron energy, 300 μA ionization current
• FI conditions: cathode potential −10 kV, emitter current 0 mA

Results and Discussion

EI spectra of isocyanate and pyrazole monomers showed low or absent molecular‐ion peaks, complicating molecular-weight confirmation. In contrast, FI generated clear molecular‐ion signals (M+·) for all four monomers. This demonstrates that the soft ionization process of FI preserves labile functional groups and yields more informative mass spectra for reactive analytes.

Benefits and Practical Applications

FI on the AccuTOF GC platform offers:

• Enhanced detection of molecular ions for reactive monomers
• Improved structural elucidation and purity assessment in polymer research
• Reduced fragmentation, simplifying spectral interpretation

Future Trends and Applications

Ongoing developments may include:

• Integration of high-resolution time-of-flight analyzers for exact-mass determination
• Automated FI emitter regeneration to extend continuous operation
• Expansion to in situ polymerization monitoring and process analytics
• Application to a broader range of labile or thermally sensitive materials

Conclusion

The FI method combined with AccuTOF GC significantly outperforms EI for analyzing monomers with highly reactive substituents. Field ionization provides robust molecular-ion detection and facilitates reliable characterization of advanced polymer building blocks.

References

• JEOL MS Data Sheet No.040 and No.089, JEOL Ltd., 2006.