New Insights from TD-GC-MS Data on Microplastics in Salt Samples

Analyzing Microplastics in the Environment
Oral Presentation

Prepared by J. Mayser1, L. Miles2, C. Widdowson2, C. Gil1
1 - Markes International GmbH, Bieberer Straße 1-7, Offenbach am Main, Hessen, 63065, Germany
2 - Markes International Ltd, 1000B Central Park, Western Avenue, Bridgend, CF31 3RT, United Kingdom

Contact Information: [email protected]; +491722819658


Detecting and analysing microplastics in the environment is challenging. The method must be able to detect and distinguish between a large variety of polymers. Additives, such as hardeners, flame retardants and preservatives, used during the manufacturing process and other compounds, that can adhere to the surfaces of microplastics from their environment, can affect their toxicity assessment. These additives could be used to link the microplastics found in the environment to their original use or potentially even back to the manufacturer.
In this study, various salts were sampled and filtered and analyzed for their microplastic content. TD–GC–MS was used to identify and measure which concentration of the plastic PS, PET, PVC and Nylon 6 had been incorporated into the crystalline structure of the salt during evaporation. By using direct desorption and backflushing technology, a large sample size could be easily isolated from the lab environment during analysis while ensuring a large range of volatile organic compounds (VOCs) including the marker compounds for four polymers could be trapped and analyzed.
The VOC-profile of the microplastics not only gave information about the polymer and its concentration within the sample, but further information about the toxicity could be extracted. This enabled the determination and tentative identification of additional compounds in the samples, such as dimethyl ether, acrolein and cyclopentane. These are used in the process of manufacturing plastics, so could assist with identifying the source of the plastics. For the four analysed polymers distinct marker compounds could be identified and calibration curves determined for each polymer. In all of the real-world salt samples microplastics were identified, highlighting the ubiquitous nature of the microplastic contamination.
This further information about the origin of the polymer, as well as the origin of the microplastic particles can be gathered by investigating the full VOC-profile obtained by TD-GC-MS. This allows both polymer and particle source characterization simultaneously.