Analysis of Food Wrap Films Using Double-Shot Pyrolyzer®Part 2: Analysis of Polyvinylidene chrolide(PVDC) by EGA Heart-Cut GC/MS Technique

Significance of the Topic

The assessment of PVDC-based food wrap films is vital in ensuring food safety and quality by monitoring plasticizers and degradation by-products that can affect barrier performance and consumer health.

Study Objectives and Overview

This work demonstrates the use of double-shot pyrolyzer with an evolved gas analysis heart-cut GC/MS approach to identify and profile volatile and semi-volatile components released from PVDC films across defined temperature zones.

Methodology and Instrumentation

Samples of PVDC film were pyrolyzed from 40 to 600°C at 20°C/min using a double-shot pyrolyzer. Specific temperature zones were isolated by a MicroJet cryo-trap (–196°C) for targeted GC/MS analysis. Gas chromatography was performed with a 5% diphenyl dimethyl polysiloxane column under helium flow.

Instrumentation details:

• Double-Shot Pyrolyzer for programmed and flash pyrolysis
• MicroJet Cryo-Trap (MJT-1030E)
• GC/MS system equipped with Ultra ALLOY-5 column (30 m × 0.25 mm × 0.25 µm)
• Carrier gas: Helium at 1 mL/min; split injection
• Oven program: 40°C (1 min) to 320°C at 20°C/min; injector at 320°C

Key Results and Discussion

The EGA profile revealed three thermal zones: Zone A (40–200°C) released low-boiling compounds such as butanol, acetic acid, and plasticizers (tributyl aconitate, tributyl acetylcitrate). Zone B (200–240°C) showed continued plasticizer release and HCl formation from PVDC dehydrochlorination. Zone C (240–500°C) produced HCl and aromatic degradation products including benzene, chlorobenzene, dichlorobenzene, and trichlorobenzene.

Benefits and Practical Applications

This targeted EGA heart-cut GC/MS method enables comprehensive compositional profiling of polymer films, supports quality control in film production, ensures compliance in food packaging, and aids forensic polymer analysis.

Future Trends and Applications

Advancements may include coupling with comprehensive two-dimensional GC, real-time chemometric data analysis, and expansion to other polymer types. These enhancements will improve sensitivity, throughput, and in situ monitoring of material degradation.

Conclusion

The double-shot pyrolyzer EGA heart-cut GC/MS technique effectively differentiates thermal degradation products of PVDC films, providing detailed insight into plasticizer content and dehydrochlorination pathways.

References

Hosaka et al., 49th Japan Analytical Society Meeting, 2000