How to Kickstart Your Micro- and Nanoplastics PY-GC/MS Analysis

Significance of the Topic

Microplastics and nanoplastics are ubiquitous pollutants that result from the fragmentation of larger plastic debris. Their minute size enables widespread distribution in aquatic and terrestrial systems. Precise identification and quantification of these particles are essential to assess environmental load, toxicological risks, and to guide remediation strategies.

Goals and Overview of the Study

This study aims to establish a robust pyrolysis-GC/MS workflow for the sensitive detection of seven common polymers in complex microplastic samples. By combining evolved gas analysis (EGA) and single shot pyrolysis, the work seeks to identify a unique thermal decomposition product (characteristic pyrolyzate) for each target polymer, facilitating selective identification and quantification.

Methodology and Instrumentation

The method couples a Frontier Lab EGA/PY-3030D multi-shot pyrolyzer with a Shimadzu GCMS-QP2020 NX system. Initial EGA mode scans samples from 100 °C to 700 °C to determine optimal pyrolysis temperatures. Single shot analyses are performed at 600 °C to generate chromatographic pyrograms. Key operating parameters include:

• Carrier gas: Helium; split ratio 100:1; injection port 300 °C
• GC column: SH-Rxi-5MS (30 m × 0.25 mm × 0.25 µm); EGA inlet tube 2.5 m × 0.15 mm
• Oven program: 40 °C for 4 min, ramp 20 °C/min to 280 °C, hold 7 min
• MS: scan m/z 29–400; ion source 230 °C; interface 280 °C
• Pyrolyzer furnace: EGA ramp 20 °C/min to 700 °C; single shot isothermal 600 °C

Instrumentation used includes: Shimadzu GCMS-QP2020 NX, Frontier EGA/PY-3030D pyrolyzer, AS-1020E autosampler, F-Search library.

Main Results and Discussion

EGA results established thermal degradation zones between 500 °C and 600 °C for all seven polymers, with 600 °C selected for single shot pyrolysis. Single shot pyrograms revealed unique marker compounds for each polymer, as follows:

• ABS: 2-phenethyl-4-phenylpent-4-enenitrile
• Nylon-6: ε-caprolactam
• Nylon-6,6: cyclopentanone
• PET: benzophenone
• PP: 2,4-dimethyl-1-heptene
• PS: styrene trimer
• PVC: naphthalene

Analysis of a mixed standard confirmed that these characteristic pyrolyzates enable selective identification and quantification in complex matrices.

Benefits and Practical Applications of the Method

This pyrolysis-GC/MS approach offers:

• Minimal sample preparation without solvent extraction
• High tolerance to complex environmental matrices
• Fast, reproducible workflows with straightforward calibration
• Quantitative mass-based measurement of polymer load
• Enhanced specificity via characteristic pyrolyzate selection

Future Trends and Opportunities

Future developments may include integration with high-resolution mass spectrometry, automation of data processing using expanded spectral libraries, coupling with microimaging techniques, and adaptation for quantitative nanoplastic analysis in diverse environmental and biological samples.

Conclusion

The combined EGA and single shot pyrolysis-GC/MS workflow delivers a reliable platform for the selective detection and quantification of common microplastics. Determination of polymer-specific characteristic pyrolyzates at an optimized temperature of 600 °C overcomes interferences and supports environmental monitoring and risk assessment efforts.

References

1. Ishimura T. et al. Qualitative and quantitative analysis of mixture of microplastics in the presence of calcium carbonate by pyrolysis-GC/MS. Journal of Analytical and Applied Pyrolysis. 2021;157:105188.
2. Pipkin W. et al. Identification of Microplastics in Environmental Monitoring Using Pyrolysis-GC-MS Analysis. LCGC North America. 2021;39(4):179–186.
3. Tsuge S. et al. Pyrolysis-GC/MS Data Book of Synthetic Polymers: Pyrograms, Thermograms and MS of Pyrolyzates. 2011.