Development and validation of an analytical pyrolysis method for detection of airborne polystyrene nanoparticles

Microplastic is ubiquitous in the environment. Recently it was discovered that microplastic (MP, 1 μm−5 mm) contamination is present in the atmosphere where it can be transported over long distances and introduced to remote pristine environments. Sources, concentration levels, and transportation pat...

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Bibliographic Details
Published in:Journal of Chromatography A Vol. 1717; p. 464622
Main Authors: Hasager, Freja, Björgvinsdóttir, Þuríður N., Vinther, Sofie F., Christofili, Antigoni, Kjærgaard, Eva R., Petters, Sarah S., Bilde, Merete, Glasius, Marianne
Format: Journal Article
Language:English
Published: Netherlands Elsevier B.V 22-02-2024
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Summary:Microplastic is ubiquitous in the environment. Recently it was discovered that microplastic (MP, 1 μm−5 mm) contamination is present in the atmosphere where it can be transported over long distances and introduced to remote pristine environments. Sources, concentration levels, and transportation pathways of MP are still associated with large uncertainties. The abundance of atmospheric MP increases with decreasing particle size, suggesting that nanoplastics (NP, <1μm) could be of considerable atmospheric relevance. Only few analytical methods are available for detection of nanosized plastic particles. Thermoanalytical techniques are independent of particle size and are thus a powerful tool for MP and NP analysis. Here we develop a method for analysis of polystyrene on the nanogram scale using pyrolysis gas chromatography coupled to mass spectrometry. Pyrolysis was performed using a slow temperature ramp, and analytes were cryofocused prior to injection. The mass spectrometer was operated in selected ion monitoring (SIM) mode. A lower limit of detection of 1±1 ng and a lower limit of quantification of 2±2 ng were obtained (for the trimer peak). The method was validated with urban ▪ matrices of low (7 μg per sample) and high (53 μg per sample) aerosol mass loadings. The method performs well for low ▪ loadings, whereas high ▪ loadings seem to cause a matrix effect reducing the signal of polystyrene. This effect can be minimized by introducing a thermal desorption step prior to pyrolysis. The study provides a novel analysis method for qualitative and semi-quantitative analysis of PS on the nanogram scale in an aerosol matrix. Application of the method can be used to obtain concentration levels of polystyrene in atmospheric MP and NP. This is important in order to improve the understanding of the sources and sinks of MP and NP in the environment and thereby identify routes of exposure and uptake of this emerging contaminant. •Novel analysis method for atmospheric polystyrene nanoparticles.•Novel pyrolysis temperature profile using a slow temperature ramp.•Detection limit of polystyrene <1 ng.•Matrix effect found at high but not low levels of urban PM2.5.•A thermal desorption step is recommended for ambient aerosol samples.
ISSN:0021-9673
1873-3778
DOI:10.1016/j.chroma.2023.464622