Quantifying Microplastics in Meconium Samples Using Pyrolysis–GC-MS

Scientists from Fudan University and the Putuo District Center for Disease Control and Prevention in Shanghai, China used pyrolysis-gas chromatography/mass spectrometry (Py–GC-MS) to detect microplastics in meconium samples. Their findings were published in the Journal of Chromatography A (1).

Microplastics Laboratory Analysis | Image Credit: © Microgen - stock.adobe.com

Global plastic production has surged to 348 million tons in 2017; however, approximately 21% of plastics are recycled, with the remainder accumulating in the environment (2). Plastics degrade due to factors such as ultraviolet radiation and mechanical wear, producing microplastics, or plastics with a diameter of less than 5 mm. Microplastics can contaminate waters, salt, and food products, such as seafood and beer. Human exposure occurs primarily through ingestion, inhalation, and skin content, the former two being the dominant pathways. Microplastics may impair reproductive health, raising concerns about developmental toxicity and long-term effects on health, with fetuses being particularly vulnerable to pollutant exposure. As a result, many scientists are investigating the health impacts of prenatal microplastic exposure.

However, extrapolating experimental doses to real-world human exposure remains challenging due to limited internal exposure data. Meconium, or the first stool of newborns, can reflect cumulative fetal exposure during gestation. It builds up inside babies’ intestines from swallowing amniotic fluid, the fluid that surrounds and cushions them inside a uterus (3). Further, meconium’s non-invasive collection and integrative biomarker potential make it an ideal matrix for assessing prenatal exposure to exogenous substances. However, accurate microplastics in meconium samples have not been quantified and reported.

Particle-based techniques, such as Fourier transform infrared (FT-IR) microscopy and Raman spectroscopy can provide particle-specific data and directly observe the number, size, and shape of plastic particles, among others. However, they can have high requirements for pretreatment and hold significant limitations in detecting particle size. Pyrolysis gas chromatography-mass spectrometry (Py–GC-MS) could present an alternative to particle-based methods, with MS identifying the characteristic pyrolyzates of microplastics and chromatographic peaks providing mass concentration information. This technique has been widely used to detect microplastics in biological samples, such as blood, but not in meconium.

In this study, the scientists developed and validated a Py–GC-MS-based analytical method for quantifying eight typical microplastics (polyethylene [PE], polypropylene [PP], polystyrene [PS], acrylonitrile-butadiene-styrene copolymer [ABS], polymethyl methacrylate [PMMA], polycarbonate [PC], polyvinyl chloride [PVC], and polyethylene terephthalate [PET]) in meconium samples. The method was used for batch testing 60 samples, which were collected from the Preconceptional Offspring Trajectory Study in Shanghai (PLOTS), a prospective cohort designed to assess how environmental factors, social determinants, lifestyle choices, and healthcare service use influence fertility, pregnancy outcomes, and child health.

Based off the existing methods, the digestion conditions and processing flow were improved. With this method, the mass concentration of the eight microplastics were accurately quantified in meconium. The method performed well, displaying good linearity (R² > 0.99), and high precision (RSD < 14.85%). Concentrations of the 8 target microplastics ranged from 1.6 × 10^-3 to 1.53 × 10⁴ μg/g, and the detection rate ranging from 51.67% to 71.67%. Overall, the method proved capable of effectively and accurately quantifying microplastics in meconium and the evaluation of health effects.

References

(1) Li, J.; Wang, K.; Lin, Z.; et al. Detection and Quantification of Microplastics in Meconium by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). J. Chromatogr. A 2025, 1749, 465868. DOI: https://doi.org/10.1016/j.chroma.2025.465868

(2) Wu, P.; Huang, J.; Zheng, Y.; et al. Environmental Occurrences, Fate, and Impacts of Microplastics. Ecotoxicol. Environ. Saf. 2019, 184, 109612. DOI: 10.1016/j.ecoenv.2019.109612

(3) Meconium. Cleveland Clinic 2022. https://my.clevelandclinic.org/health/body/24102-meconium (accessed 2025-3-25)