1.1 本试验方法描述了使用电感耦合等离子体发射光谱法（ICP-OES；还包括ICP-AES，其中AES是原子发射光谱法）或电感耦合等离子体质谱法（ICP-MS）测定胶体金悬浮液中颗粒结合金（Au）的质量分数。颗粒结合金定义为与纳米颗粒（NP）部分相关并强烈吸附到颗粒表面的金质量。未结合金是自然悬浮液中与金纳米粒子部分无关的金部分，即溶液中以络合物或自由离子形式存在的溶解金。颗粒结合金的质量分数是通过从胶体金悬浮液的酸消解子样品中测量的总金质量分数减去在无颗粒上清液的酸化子样品中测量的未结合金的质量分数来确定的。 离心胶体金悬浮液后获得无颗粒上清液。本标准规定了使用适当的内部标准，并使用外部标准或单点标准添加进行校准。 1.2 AuNP直径为1 nm至100 nm的胶体金悬浮液可以用该方法测定。 1.3 本标准不限于具有均匀金成分的颗粒，并可适用于具有金壳处理的核壳颗粒。 1.4 本标准针对Au。该方法可能适用于通过ICP-OES或ICP-MS测量的其他元素，但仅限于在水悬浮液中不反应的纳米粒子。 1.5 由于不同品牌和型号之间的差异，没有提供操作仪器的详细说明。相反，分析员应遵循特定ICP制造商提供的说明- OES、ICP-MS或离心机仪器，尤其是在优化仪器设置方面。 1.6 以国际单位制表示的数值应视为标准值。本标准不包括其他测量单位。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 各种形状的金纳米物体（即棒状、颗粒）越来越多地用于各种应用。靶向给药、肿瘤检测和治疗等AUNP的医学应用越来越普遍 ( 5. ) . AUNP具有与其尺寸相关的独特光学性质，其表面可以很容易地进行功能化。虽然金被认为是惰性和生物相容性的，但必须测试金纳米物体在生物系统和环境中的行为，以确保其惰性和安全性 ( 6. ) . 重要的是要知道制备和储存的AUNP悬浮液是否含有处于结合状态（通常为Au（0）和颗粒吸附物种）或电离状态（通常为Au（I）或Au（III））的Au，以将生物反应归因于适当的物种。Krug等人得出结论，在研究之前和研究期间未对纳米材料悬浮液的材料特性进行表征的情况下，毒性研究的重要性大大降低 ( 7. ) . 此外，利用颗粒结合物种的分析物质量分数和粒径知识计算颗粒数浓度。

1.1 This test method describes the use of inductively coupled plasma optical emission spectrometry (ICP-OES; also includes ICP-AES, where AES is atomic emission spectrometry) or inductively coupled plasma mass spectrometry (ICP-MS) for the determination of the mass fraction of particle bound gold (Au) in colloidal Au suspensions. Particle bound Au is defined as the mass of Au associated with the nanoparticle (NP) fraction and strongly adsorbed to the particle surface. Unbound Au is the fraction of Au in the native suspension not associated with the Au nanoparticle fraction that is, the dissolved Au existing in solution as a complex or free ion. The mass fraction of particle bound Au is determined by subtracting the mass fraction of unbound Au measured in acidified subsamples of the particle-free supernatant from the total Au mass fraction measured in acid-digested subsamples of the colloidal Au suspension. The particle-free supernatant is obtained after centrifugation of the colloidal Au suspension. This standard prescribes the use of an appropriate internal standard and calibration using either external standardization or single-point standard additions. 1.2 Colloidal gold suspensions with AuNP diameters ranging from 1 nm to 100 nm can be determined with this method. 1.3 The standard is not limited to particles with a uniform Au composition and may be applicable to a core-shell particle with a Au shell treatment. 1.4 This standard is specific to Au. The method may be applicable to other elements measurable by ICP-OES or ICP-MS but is limited to nanoparticles that are not reactive in aqueous suspension. 1.5 No detailed instructions for operating instrumentation are provided because of differences among various makes and models. Instead, the analyst shall follow the instructions provided by the manufacturer of their particular ICP-OES, ICP-MS or centrifuge instrument, especially with regard to optimization of the instrument settings. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurements are included in this standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Au nano-objects in various shapes (that is, rods, particles) are increasingly used for a wide variety of applications. Medical applications of AuNPs, such as targeted drug delivery, tumor detection, and treatment are becoming more common ( 5 ) . AuNPs have unique optical properties related to their size and their surface can be readily functionalized. Though Au is recognized to be inert and biocompatible in its bulk form, the behavior of Au nano-objects in biological systems and the environment must be tested to ensure their inertness and safety ( 6 ) . It is important to know whether prepared and stored suspensions of AuNPs contain Au in its bound state (commonly Au (0) and particle adsorbed species) or ionized state (commonly, Au (I) or Au (III)) to attribute the biological response to the appropriate species. Krug, et al., concluded that the significance of toxicity studies is considerably reduced in those cases where the material properties of the nanomaterial suspensions were not characterized prior to and during the study ( 7 ) . Furthermore, the analyte mass fraction of particle bound species is used with knowledge of particle size to compute particle number concentration.