1.1 激光放大检测/功率谱分析（LAD/PSA）技术可在三个不同的平台上使用，这三个平台将被指定为平台A、B和C。 1.1.1 平台A-- 这是一种固态探针配置，用作每个平台中的光学工作台。它由一个带有y分束器的光纤耦合器组成，该分束器将来自纳米颗粒的散射光信号以180°的角度引导回光电二极管检测器。探针的感测端可以浸入悬浮液中，或者定位为测量感测表面顶部的一滴样品。 1.1.2 平台B-- 将相同的探针安装在水平放置的外壳中，以检测来自一次性或永久性试管的信号。 1.1.3 平台C-- 两个探针水平安装在一个外壳中，位于永久样品池的相对两侧。在这种配置中可以测量尺寸分布和ζ电势。 1.2 在所有三个平台中，穿过探针测量来自纳米颗粒样品的散射光的激光束被部分反射回同一光电二极管检测器，并且激光的高光功率被添加到散射光信号的低光功率中。这两个信号的干扰（混合或拍频）称为外差拍频。产生的高功率检测信号提供最高信号- 动态光散射（DLS）技术中的噪声比。 1.3 这种组合的、放大的光信号通过快速傅立叶变换（FFT）转换为频率功率谱，然后转换为对数功率谱，对数功率谱被去卷积为数量和体积大小分布。可以在所有平台中报告平均强度、多分散性、数量和体积尺寸分布、浓度和分子量，以及平台C上的ζ电势。 1.4 该技术能够测量2.0尺寸范围内的纳米颗粒 纳米（nm）到10 微米（µm），在悬浮液体介质中的浓度高达40 % 中给出的所有参数的cc/mL 1.3 . 1.5 单位-- 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 在本指南中，描述了使用激光放大检测/功率谱分析（LAD/PSA）技术在三个不同的仪器平台上测量纳米颗粒性质的几个特征的条件、测量设备和程序。这是一种较新开发的技术，于1990年商业化，而不是1961年首次开发的光子相关光谱（PCS）或准弹性光散射（QLS）这两种技术——这些名称是可互换的。纳米粒子跟踪分析（NTA）是最新商业化的DLS技术。 这三种技术都属于更广泛的DLS范畴，基于布朗运动下测量的纳米颗粒的“动态”运动。 4.2 随着粒子光学散射系数急剧下降，降低散射光强度，纳米尺寸范围下端的DLS变得越来越困难。将解释外差检测模式相对于零差检测模式的优点，特别是在纳米范围的低端。 4.3 将描述LAD/PSA技术，并明确其与PCS-QLS和NTA技术之间的主要区别。 有关PCS-QLS的详细讨论，请参阅指南 E2490 ，试验方法 E3247 和ISO 22412附录第A.1节。有关纳米粒子跟踪分析（NTA）的详细讨论，请参阅指南 E2834 有关激光放大检测/频率功率谱（LAD/FPS）技术的详细信息，请参阅ISO 22412附录第A.2节。有关颗粒表征实践的一般信息可在实践中找到 E1817 ，纳米技术术语在术语中给出 E2456 有关颗粒表征取样的详细信息可参见ISO 14488。

1.1 The technology, laser-amplified detection/power spectrum analysis (LAD/PSA), is available in three different platforms, which will be designated as Platforms A, B, and C. 1.1.1 Platform A— This is a solid-state probe configuration that serves as the optical bench in each of the platforms. It consists of an optical fiber coupler with a y-beam splitter that directs the scattered light signal from the nanoparticles at 180° back to a photodiode detector. The sensing end of the probe can be immersed in a suspension or positioned to measure one drop of a sample on top of the sensing surface. 1.1.2 Platform B— The same probe is mounted in a case, positioned horizontally, to detect the signal from either a disposable or permanent cuvette. 1.1.3 Platform C— Two probes are mounted in a case, horizontally, at opposite sides of a permanent sample cell. Both size distribution and zeta potential can be measured in this configuration. 1.2 The laser beam travelling through the probe measuring the scattered light from the sample of nanoparticles, in all three platforms, is partially reflected back to the same photodiode detector, and the high optical power of the laser is added to the low optical power of the scattered light signal. The interference (mixing or beating) of those two signals is known as heterodyne beating. The resulting high-power detected signal provides the highest signal-to-noise ratio among dynamic light-scattering (DLS) technologies. 1.3 This combined, amplified, optical signal is converted with a Fast Fourier transform (FFT) into a frequency power spectrum, then into a logarithmic power spectrum that is deconvolved into number and volume size distributions. The mean intensity, polydispersity, number and volume size distributions, concentration, and molecular weight can be reported in all platforms, plus zeta potential on Platform C. 1.4 This technology is capable of measuring nanoparticles in a size range from 2.0 nanometres (nm) to 10 micrometres (µm), at concentrations in a suspending liquid medium up to 40 % cc/mL for all parameters given in 1.3 . 1.5 Units— The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.6 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. 1.7 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 ====== 4.1 In this guide, the conditions, measurement apparatus, and procedures for measuring several characteristics of nanoparticle properties on three different instrument platforms using laser-amplified detection/power spectrum analysis (LAD/PSA) technology are described. This is a more recently developed technology, commercialized in 1990, than the older technology known as either photon correlation spectroscopy (PCS) or quasi-elastic light scattering (QLS)—those titles are interchangeable—developed first in 1961. Nanoparticle tracking analysis (NTA) is the most recent DLS technology to be commercialized. All three of these technologies fall under the broader category of DLS, based on the “dynamic” movement of the measured nanoparticles under Brownian motion. 4.2 DLS in the lower end of the nanometre size range becomes progressively more difficult as the particle optical scattering coefficients drop sharply, reducing the scattered light intensity. The advantage of the heterodyne detection mode over the homodyne detection mode, especially at the low end of the nanometre range, will be explained. 4.3 The LAD/PSA technology will be described and the major differences between it and the PCS-QLS and NTA technologies will be made clear. For thorough discussions of PCS-QLS, refer to Guide E2490 , Test Method E3247 , and ISO 22412 Annex Section A.1. For a thorough discussion of nanoparticle tracking analysis (NTA), refer to Guide E2834 . For detailed information on laser-amplified detection/frequency power spectrum (LAD/FPS) technology, refer to ISO 22412 Annex Section A.2. General information on particle characterization practices can be found in Practice E1817 , and nanotechnology terminology is given in Terminology E2456 . Detailed information on sampling for particle characterization can be found in ISO 14488.