PY-GCMS Analysis of Microplastics Using Nitrogen as an Alternative GCMS Carrier Gas

Analyzing Microplastics in the Environment
Oral Presentation

Presented by R. Marfil-Vega
Prepared by A. Sandy, E. Wang, Y. Okamura, A. Owens
Shimadzu Scientific Instruments, 7102 Riverwood Drive, Columbia, MD, 21046, United States


Contact Information: [email protected]; 410-910-0884

ABSTRACT

Pyrolysis GCMS is a proven technique for analyzing microplastics (MP). Conventionally, helium has been used as a carrier gas for this analysis. However, due to the low global supply of helium, it’s critical for laboratories to find alternatives. This study explores the use of Py-GCMS using nitrogen as a carrier gas for the measurement of microplastics in environmental samples using the Shimadzu GCMS-QP2020NX coupled to a Frontier multi-shot Py-3030D pyrolyzer.
Using a MPs-CaCO3 standard, a six-point calibration curve was prepared for most compounds, except for polystyrene (five points). A short-term repeatability test was conducted at the lower and upper end of the calibration range. The accuracy of each standard was calculated using theoretical concentration for each compound. The method LLOQ was determined using 0.4 mg total mass standard.
Calibration results showed good coefficient of determination (r2) > 0.990 for all analytes. The accuracy of each replicate calibrant mostly range between 80 -120 %. The calibration curve was linear for most polymers, except for PU, ABS and PS that had a quadratic fit. Percent RSD for each target polymer replicates at 0.4 mg and 3 mg standards ranged from 0.8 to 6.6 and 2.0 to 8.4, respectively. All compounds were within an RSD of 10 %. LLOQ for all polymers ranged from 0.21 to 14.58 µg. The accuracy of the method calculated using 0.4 mg standard mass ranged from 102.6 to 133.8 and at 3 mg from 101.3 to 109.2, except for PS (mass of polymer was outside the calibration range). The study demonstrated the satisfactory performance of the method. In this presentation we will share the detailed results from this study and their comparison to a Helium-based method.