Dye tracing

Dye tracing is a method of tracking and tracing various flows using dye as a flow tracer when added to a liquid. Dye tracing may be used to analyse the flow of the liquid or the transport of objects within the liquid. Dye tracking may be either qualitative, showing the presence of a particular flow, or quantitative, when the amount of the traced dye is measured by special instruments. Dye tracing is a method of tracking and tracing various flows using dye as a flow tracer when added to a liquid. Dye tracing may be used to analyse the flow of the liquid or the transport of objects within the liquid. Dye tracking may be either qualitative, showing the presence of a particular flow, or quantitative, when the amount of the traced dye is measured by special instruments. Fluorescent dyes are often used in situations where there is insufficient lighting (e.g., sewers or cave waters), and where precise quantitative data are required (measured by a fluorometer). In 1871, Fluorescein was among the first fluorescent dyes to be developed. 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 fluorescence that is present in a liquid sample. Different dyes and chemicals produce a distinctive wavelength that is determined during analysis.