Simultaneous Determination of Six Common Microplastics by a Domestic Py-GC/MS

Pyrolysis coupled with gas chromatography–mass spectrometry (Py-GC/MS) is a novel technology capable of detecting micro- and nanoplastics without a size limit. However, the application of Py-GC/MS to airborne microplastic analysis remains inconsistent. This study explores optimal Py-GC/MS procedures using a domestic HenxiTM PY-1S pyrolyzer-based Py-GC/MS. The initial weight loss of PVC occurs at approximately 260 °C, indicating that the maximum thermal desorption temperature prior to pyrolysis should not exceed 250 °C. To avoid interference from semi-volatile organics present in the sample and injected air, it is essential to purge the sample with pure helium at elevated temperatures before pyrolysis. Microplastic standards can be prepared by ultrasonicating a water–microplastic dispersion system. Significant interactions between microplastic mixtures were observed during co-pyrolysis, indicating that the interactions of mixtures cannot be ignored during the optimization of quantitative references. The optimal procedure features good linearity (R2 > 0.98), low detection limit (0.06~0.0002 μg), and acceptable precisions (RSD < 10% in 8 days). Microplastics determined by the domestic PY-1S pyrolyzer coupled with a GC/MS system are comparable to those of the well-established PY-3030D-based Py-GC/MS, indicating that the domestic pyrolyzer coupled with GC/MS is a reliable and powerful tool for microplastic analysis.