Nanopartikelsporingsanalyse

Nanopartikelsporingsanalyse, often abbreviated as NTA, is a technique used to determine the size distribution of nanoparticles in a liquid suspension. It works by observing the Brownian motion of individual nanoparticles. When a laser beam illuminates the sample, the nanoparticles suspended in the liquid scatter light. As these nanoparticles move randomly due to collisions with the molecules of the surrounding liquid, their scattered light also fluctuates. NTA detects these fluctuations and analyzes them to infer the size of each particle.

The principle behind NTA is that larger particles move slower than smaller particles due to Brownian motion. By tracking the displacement of each particle over time, the technique can calculate a diffusion coefficient for that particle. This diffusion coefficient is directly related to the particle's hydrodynamic diameter through the Stokes-Einstein equation. NTA instruments typically use a camera or a sensitive detector to record the scattered light from many particles simultaneously, allowing for the analysis of a broad size distribution in a relatively short time.

NTA is a powerful tool for characterizing nanoparticles in various fields, including materials science, pharmaceuticals, and biotechnology. It offers advantages such as direct measurement of individual particles, providing a true size distribution without relying on assumptions about particle shape or refractive index, which can be limitations for other techniques like dynamic light scattering. The analysis is performed on samples in their native liquid state, avoiding the need for complex sample preparation. This makes NTA a convenient and widely applicable method for nanoparticle characterization.