Qualitative and Quantitative Analysis of Tire Wear\nParticles (TWPs) in Road Dust Using a Novel Mode of Operation of TGA-GC/MS

Detecting and quantifying\ntire wear particles (TWPs) in the environment\npose a unique environmental challenge due to their chemical complexity.\nThere are emerging concerns around TWPs due to their potential high\nnumbers of particles released, outnumbering microplastics, as well\nas the leaching of toxic additives such as 6-PPD which has been linked\nto the death of salmon even when present at very low levels (<0.1\nμg/L). Analytical techniques such as pyrolysis gas chromatography\nmass spectrometry (Py-GC/MS) and thermal extraction-desorption gas\nchromatography mass spectrometry (TED-GC/MS) have been used but also\ndemonstrate limitations including low sample mass, low sample throughput,\nand complex characterization and quantification procedures. This work\naims to overcome these challenges by developing a new approach which\nutilizes a coupling between thermogravimetric analysis (TGA) and gas\nchromatography–mass spectrometry (GC/MS). This work is the\nfirst to harness conventional TGA-GC/MS for the analysis of tire rubber,\nwith the detection of additives such as 6-PPD, while also pioneering\na novel mode of operation, PyroTGA-GC/MS, using fast heating to enable\nrobust quantitative analysis of TWPs in road dust. The limits of detection\nand quantification of 0.08/0.16 μg and 0.20/0.40 μg for\nSBR and PI, respectively, are lower than those achieved using Py-GC/MS\nand TED-GC/MS for SBR and align with those achieved for PI. This study\nreveals a clear link between the ratio of PI to SBR and the proportion\nof heavy goods vehicles. This work solves key issues in tire particle\nanalysis related to sample size and throughput. By overcoming these\nlimitations, we introduce a technique that provides an economically\nviable solution for large-scale commercial analysis of tire rubber\nand particles.