Analysis of advanced materials by FD/FI using “AccuTOF GC” - analysis of organic borates, photoinitiators for polymerization

Significance of the Topic

The analysis of organic borate ammonium salts by field desorption (FD) coupled to high-resolution time-of-flight mass spectrometry addresses the need for soft ionization techniques capable of characterizing nonvolatile photoinitiators. Accurate mass spectral data support the design and quality control of functional polymers in industrial and research laboratories.

Objectives and Study Overview

This work investigates three quaternary borate ammonium salts used as photoinitiators for polymerization. The goals were to evaluate FD+ ionization behavior, determine which ionic species are detected, and assess the ability to discern cationic and anionic fragments under mild desorption conditions.

Methodology

Samples of P3B, BP3B and N3B salts were prepared on nickel emitters. Field desorption ionization was induced by applying a cathode potential of –10 kV with an emitter current ramp up to 40 mA. Spectra were acquired over m/z 30–900 at 0.3-second intervals to capture both molecular and fragment ions.

Instrumentation Used

• AccuTOF GC JMS-T100GC (JEOL Ltd.)
• FD+ ion source with nickel wire emitters
• TOF analyzer for high-resolution mass detection

Main Results and Discussion

The quaternary ammonium cation [C16H36N]+ at m/z 242 appeared as the base peak in all spectra. Molecular ions combining cation and anion were not observed. Deprotonated anion [(Anion)–H]+ peaks were detected weakly for each compound. BP3B and N3B also yielded fragment peaks corresponding to loss of n-butyl groups at m/z 401 and 392, respectively. These findings demonstrate selective cleavage of the anion moiety while preserving the stable quaternary ammonium core.

Benefits and Practical Applications

• Soft ionization preserves structural integrity of nonvolatile initiators.
• Cationic core provides a reliable reference peak for compound identification.
• Detection of anionic fragments enables assessment of borate structure and purity.
• Applicable to QA/QC in polymer additive production.

Future Trends and Applications

Advances in emitter design and coupling FD with tandem MS will improve sensitivity for trace photoinitiators. Integration with chromatography may expand applicability to complex mixtures. Machine-learning algorithms for spectral interpretation could accelerate identification of novel borate derivatives in polymer research.

Conclusion

Field desorption on the AccuTOF GC platform effectively detects quaternary ammonium cations and related anion fragments from organic borate salts. The method offers a robust approach for soft ionization analysis of photoinitiators, supporting both research and industrial quality control.

Reference

JEOL MS Data Sheet, Mass Spectrometry Application Group, JEOL Ltd., 2006.