Tracerpartikel

A tracer particle, or tracerpartikel, is a small particle introduced into a system to follow its movement, transport, or reaction pathways. The goal is to observe how a fluid moves, how substances diffuse, or how chemical or biological processes proceed, with minimal disruption to the system.

Tracer particles are labeled with detectable signals. They can be radioactive isotopes, fluorescent dyes or nanoparticles, or magnetically responsive materials. Common choices include inert microbeads, quantum dots, or labeled silica spheres, selected for size, surface properties, and compatibility with the studied environment.

Applications span medicine, environmental science and industrial research. In medicine, tracers help track drug delivery or metabolic pathways. In environmental science, they reveal groundwater flow, river dispersion, or pollutant transport. In fluid mechanics, tracer particles enable flow visualization and quantification through techniques such as particle image velocimetry (PIV) and particle tracking velocimetry (PTV).

Detection relies on the tracer's label. Radiotracers are detected by radiometric instruments; fluorescent tracers are observed with optical microscopes and cameras; magnetic tracers are detected by magnetic sensors. Data from particle trajectories yield velocities, diffusion coefficients, and residence times.

Safety and limitations include potential perturbation of the system, toxicity concerns, and regulatory considerations. The tracer concentration and material are chosen to minimize impact, and measurements are interpreted within the tracer's known behavior and resolution limits.