Tire road wear particles (TRWPs) are a large source of microplastics in the environment, while the quantification of TRWPs is still challenging due to the complex interferences and the uncertainties and inconsistencies among different methods. This study developed a TRWPs quantification method using optimized pretreatments and bonded-sulfur as marker. Road dust samples (n = 48) were collected, pretreatments including density separation, digestion and extraction were optimized to remove interferences of the bonded-sulfur (minerals, sulfur-containing proteins, hydrosoluble/hydrophobic sulfur-containing substances). Presence of TRWPs in the samples was confirmed by microscopy and scanning electron microscopyenergy dispersive spectrometry. Bonded-sulfur in the samples were quantified by inductively coupled plasmamass spectrometry (ICPMS). Additionally, bonded-sulfur in tire wear particles (TWPs) abraded from tires of top 10 best-selling brands were measured to calculate conversion factor (1.1 ×104 μg/g) for the quantification of TRWPs in real samples. TRWPs contents were 5.40 × 104 μg/g11.02 × 104 μg/g and 2.36 × 104 μg/g5.30 × 104 μg/g in samples from heavy and light traffic roads, respectively. The method provided better recoveries (88–107%, n = 18) and repeatability (RSD=2.0–7.9%, n = 3) compared to methods using rubber, benzothiazole and organic zinc as markers. Furthermore, stability of the bonded-sulfur was validated by Raman and ICPMS. Thus, this accurate and stable quantification method could promote research on TRWPs.

中文翻译：

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分离和定量道路粉尘样品中的轮胎和道路磨损颗粒：键合硫作为新型标志物


轮胎路面磨损颗粒 （TRWP） 是环境中微塑料的重要来源，但由于干扰复杂以及不同方法之间的不确定性和不一致性，TRWP 的定量仍然具有挑战性。本研究开发了一种使用优化的预处理和键合硫作为标记的 TRWPs 定量方法。收集道路尘埃样品 （n = 48），优化包括密度分离、消解和萃取在内的预处理，以去除键合硫（矿物、含硫蛋白质、疏溶性/疏水性含硫物质）的干扰。通过显微镜和扫描电子显微镜能量色散谱法证实样品中存在 TRWP。通过电感耦合等离子体质谱法 （ICPMS） 对样品中的键合硫进行定量。此外，测量前 10 个最畅销品牌轮胎磨损颗粒 （TWP） 中的粘结硫，以计算转换因子 （1.1 ×104 μg/g），用于定量实际样品中的 TRWP。重、轻交通道路样品中TRWPs含量分别为5.40 × 104 μg/g、11.02 × 104 μg/g、2.36 × 104 μg/g、5.30 × 104 μg/g。与使用橡胶、苯并噻唑和有机锌作为标志物的方法相比，该方法提供了更好的回收率 （88–107%，n = 18） 和重现性 （RSD=2.0–7.9%，n = 3）。此外，拉曼光谱和 ICPMS 验证了键合硫的稳定性。因此，这种准确稳定的定量方法可以促进 TRWP 的研究。