Caceres George C, Johnson Monique E, Molloy John L, Lee Sang Bok, Montoro Bustos Antonio R
Chemical Sciences Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899-1070, United States.
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States.
Anal Chem. 2025 Sep 16;97(36):19818-19828. doi: 10.1021/acs.analchem.5c03552. Epub 2025 Sep 5.
In response to the growing concern of microplastics (1 μm to 5 mm) accumulation affecting human health, the development of analytical methods continues to be critical for the detection and characterization of microplastic particles. In this context, pursuing exceptional particle detection capability down to practical low levels and rapid analyses with high sample throughput makes single particle inductively coupled plasma mass spectrometry (spICP-MS) very attractive for microplastics analysis. Existing spICP-MS-based studies have routinely shown limitations in the accurate sizing and quantification of particle number concentration through targeting carbon content, with reported size limits of detection in the range of 0.62 to 1.8 μm and a substantial reduction in the transport of particles larger than 3 μm. In this work, the linear dynamic range of spICP-MS for the accurate quantification of polystyrene microparticles (PS MPs) via the monitoring of their carbon content (C) is extended to larger particle sizes (5 μm) through using a high efficiency sample introduction system with rigorous optimization of the C signal and operating at a lowered nebulizer gas flow to improve sample transport of larger particles to the plasma. Reliable quantification of particle number concentration (PNC), accepted as falling within 20% of expected particle stock concentrations, was achieved through a 20% lowered nebulizer gas flow for a full suite of commercial PS MPs ranging from 2 to 5 μm as well as a 2.2 and 4.8 μm PS MP contained within mixtures of the two materials, regardless of PNC ratio.
鉴于微塑料（1微米至5毫米）积累对人类健康的影响日益受到关注，分析方法的发展对于微塑料颗粒的检测和表征仍然至关重要。在这种情况下，追求极低实际水平下的卓越颗粒检测能力以及高样品通量的快速分析，使得单颗粒电感耦合等离子体质谱法（spICP-MS）在微塑料分析中极具吸引力。现有的基于spICP-MS的研究通常表明，通过靶向碳含量来准确确定颗粒尺寸和定量颗粒数浓度存在局限性，报道的检测尺寸下限在0.62至1.8微米范围内，且大于3微米的颗粒传输量大幅减少。在这项工作中，通过使用高效进样系统，对碳信号进行严格优化，并在较低的雾化器气体流速下运行，以改善较大颗粒向等离子体的样品传输，将spICP-MS通过监测聚苯乙烯微塑料（PS MPs）的碳含量（C）来准确定量的线性动态范围扩展到更大的颗粒尺寸（5微米）。对于一系列粒径从2至5微米的商用PS MPs以及包含在两种材料混合物中的2.2微米和4.8微米PS MPs，通过将雾化器气体流速降低20%，实现了颗粒数浓度（PNC）的可靠定量，其定量结果被认为在预期颗粒储备浓度的20%以内，且与PNC比例无关。
