Abram Sarah-Luise, Mrkwitschka Paul, Thünemann Andreas F, Radnik Jörg, Häusler Ines, Bresch Harald, Hodoroaba Vasile-Dan, Resch-Genger Ute
Division Biophotonics, Bundesanstalt für Materialforschung und -prüfung, Richard-Willstaetter-Straße 11, 12489 Berlin, Germany.
Division Surface Analysis and Interfacial Chemistry, Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 44-46, 12203 Berlin, Germany.
Anal Chem. 2023 Aug 22;95(33):12223-12231. doi: 10.1021/acs.analchem.3c00749. Epub 2023 Aug 11.
The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes' edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators.
纳米材料的合理设计及其在工业上日益广泛的应用，需要对其关键的物理化学性质进行可靠的表征，如尺寸、尺寸分布、形状和表面化学性质。这就需要纳米级参考材料（nanoRMs）来验证和标准化常用的表征方法，这些方法要与实际的非球形纳米物体紧密匹配。这促使我们开发一种尺寸非常小的非球形纳米参考材料，它由8纳米的氧化铁纳米立方体（BAM-N012）组成，以补充球形的金、二氧化硅和聚合物纳米参考材料。以下将重点介绍这种纳米参考材料的开发和生产，包括通过透射电子显微镜（TEM）和小角X射线散射（SAXS）进行表征，这两种方法可作为互补手段，用于确定尺寸和形状参数、研究均匀性和稳定性，以及计算尺寸特征的完整不确定度预算。通过TEM和SAXS测定纳米立方体的边长，可以进行方法比较。此外，SAXS测量还可以提供平均粒子数密度和质量浓度。通过TEM测定的经认证的尺寸参数，即面积等效圆直径和方形边长，其相对扩展不确定度低于9%，在计量学上可追溯到长度的自然常数，即硅的非常精确已知的（111）晶格间距。立方BAM-N012可作为经认证的纳米参考材料，用于评估电子显微镜和SAXS以及其他适用于纳米材料的尺寸测量方法在粒度和形状测量方面的精度和准确性、验证和质量保证。这种新型氧化铁纳米立方体参考材料的生产，对纳米材料领域、纳米材料制造商和监管机构来说是一项重要成就。
