Dye tracing

Dye tracing is tracking and tracing various flows using dye added to the liquid in question. That is, it uses dye as a flow tracer. The purpose of tracking may be an analysis of the flow itself, of the transport of something by the flow of the objects that convey the flow. It is an evolution of the ages-known float tracing method, which basically consists of throwing a buoyant object into a waterflow to see where it goes or where it emerges.

Dye tracking may be either qualitative, i.e., the presence of particular flow and its estimate, or quantitative, when the amount of the traced dye is measured by special instruments.

Often fluorescent dyes are used for this purpose, especially in the following circumstances

Fluorescein is among the first fluorescent dyes, developed in 1871. Its disodium salt under the trademark "Uranine" was developed several years later and still remains among the best tracer dyes.

Other popular tracer dyes are rhodamine, pyranine and sulforhodamine.

Carbon sampling was the first method of technology-assisted dye tracing that was based on the absorption of dye in charcoal. Charcoal packets may be placed along the expected route of the flow, later the collected dye may be chemically extracted and its amount subjectively evaluated.

Filter fluorometers were the first devices that could detect dye concentrations beyond human eye sensitivity.

Spectrofluorometers developed in the mid-1980s made it possible to perform advanced analysis of fluorescence.

Filter fluorometers and spectrofluorometers identify the intensity of fluorscence that is present in a liquid sample. Different dyes and chemicals produce a distinctive wavelength that is determined during analysis.

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