Nanoparticle Size Detection Limits by Single Particle ICP-MS for 40 Elements

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• 作者：Sungyun Lee ; Xiangyu Bi ; Robert B. Reed ; James F. Ranville ; Pierre Herckes ; Paul Westerhoff
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：September 2, 2014
• 年：2014
• 卷：48
• 期：17
• 页码：10291-10300
• 全文大小：443K
• ISSN：1520-5851

文摘

The quantification and characterization of natural, engineered, and incidental nano- to micro-size particles are beneficial to assessing a nanomaterial鈥檚 performance in manufacturing, their fate and transport in the environment, and their potential risk to human health. Single particle inductively coupled plasma mass spectrometry (spICP-MS) can sensitively quantify the amount and size distribution of metallic nanoparticles suspended in aqueous matrices. To accurately obtain the nanoparticle size distribution, it is critical to have knowledge of the size detection limit (denoted as D_min) using spICP-MS for a wide range of elements (other than a few available assessed ones) that have been or will be synthesized into engineered nanoparticles. Herein is described a method to estimate the size detection limit using spICP-MS and then apply it to nanoparticles composed of 40 different elements. The calculated D_min values correspond well for a few of the elements with their detectable sizes that are available in the literature. Assuming each nanoparticle sample is composed of one element, D_min values vary substantially among the 40 elements: Ta, U, Ir, Rh, Th, Ce, and Hf showed the lowest D_min values, 鈮?0 nm; Bi, W, In, Pb, Pt, Ag, Au, Tl, Pd, Y, Ru, Cd, and Sb had D_min in the range of 11鈥?0 nm; D_min values of Co, Sr, Sn, Zr, Ba, Te, Mo, Ni, V, Cu, Cr, Mg, Zn, Fe, Al, Li, and Ti were located at 21鈥?0 nm; and Se, Ca, and Si showed high D_min values, greater than 200 nm. A range of parameters that influence the D_min, such as instrument sensitivity, nanoparticle density, and background noise, is demonstrated. It is observed that, when the background noise is low, the instrument sensitivity and nanoparticle density dominate the D_min significantly. Approaches for reducing the D_min, e.g., collision cell technology (CCT) and analyte isotope selection, are also discussed. To validate the D_min estimation approach, size distributions for three engineered nanoparticle samples were obtained using spICP-MS. The use of this methodology confirms that the observed minimum detectable sizes are consistent with the calculated D_min values. Overall, this work identifies the elements and nanoparticles to which current spICP-MS approaches can be applied, in order to enable quantification of very small nanoparticles at low concentrations in aqueous media.