ASTM E2834-12(2018)

ASTM E2834 is a standard guide that provides recommended practices for nanoparticle tracking analysis (NTA). It does not prescribe mandatory acceptance criteria or serve as a compendial test method. The technique records and analyzes the Brownian motion of individual particles in real time, calculating their hydrodynamic diameter via the Stokes–Einstein equation. Unlike ensemble methods (e.g., DLS), NTA primarily provides number-weighted particle size distributions, which distinguishes it from ensemble methods such as DLS that report intensity-weighted averages.

• Size Range: Applicable to nanomaterials typically between ~10 nm and 1000 nm in hydrodynamic diameter.

• Medium: For particles dispersed in a liquid (aqueous or non-aqueous) with known viscosity and temperature.

• Purpose: Provides guidance for instrument setup, sample preparation, data acquisition, analysis, and reporting to improve reproducibility and inter-laboratory comparability.

• Limitations: Does not set acceptance criteria or define regulatory specifications — it is intended as best practice guidance.

• Core Principle — Brownian Motion & Stokes–Einstein Equation

  Small particles in a liquid undergo random thermal motion due to collisions with solvent molecules. The diffusion coefficient (D) obtained from tracking this motion is related to the particle’s hydrodynamic diameter (d) through the Stokes–Einstein equation