Improvement and suitability of analytical method for the detection of tire and road wear particles markers in low-concentration sediment and soil matrices

Tire and road wear particles (TRWP) are formed by the friction between the tire and road. Despite being a massive, global and emerging pollution, their quantification and tracing are currently uncertain in environments far from roads due to a lack of optimized approaches. Pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC-MS) is a central technique in environmental research devoted to the TRWP topic. Herein, we present a more sensitive and selective approach based on the Py-GC-MS technique for detecting and quantifying TRWP in matrices far from emission sources. This approach involves sample purification and analytical optimization steps focused on: i) preliminarily removing interfering organic compounds from samples, ii) choosing the most selective markers to improve peak resolution in chromatograms and iii) improving the recovery rates (up to 100 - 108%) for selected elastomers (SBR and NR). The markers that are identified for reliably quantifying elastomers in low-concentration matrices far from sources are 4-phenylcyclohexene for styrene butadiene rubber and dimethylvinylcyclohexene for natural rubber. Using internal standards for calibration and acquiring data in single ion monitoring mode allowed us to achieve limits of detection as low as 7.7 µg/g for SBR and 3.8 µg/g for NR. Finally, we evaluated the performance obtained by comparing the SBR and NR contents of low-concentration soils and sediments using our optimized Py-GC-MS technique and the Py-GC tandem mass spectrometry (Py-GC-MS/MS). • Current analytical methods not suitable for measuring low levels in environmental matrices • Improved method for detection of TRWP in matrices far from sources • Combination of chemicals pretreatment and pyrolysis-GC-MS optimization to enhance method performance • Less than 10 µg/g of limits of detection and 100 – 110% recovery rates for soil and sediment