Leak tracing and detection
UV Fluorescent Colored Tracers
UV Fluorescent Clear Tracers
Food Tracers for Water
Tracers for Oils and Fuels
Non-fluorescent color tracers
Fluorescein: fluorescent tracer for leak detection
Equipment for Tracing and Diagnostics
UV Lamp Kits
Dosing accessories and equipment
Complete Air Conditioning Tracing Kits
Complete Oil and Fuel Tracing Kits
Complete Water Tracing Kits
Smoke Generators
Inflatable Pipe Plugs
Detection needles
Tracing in Natural Environments
Fluorimeters and Data Loggers
Fluorescent Tracers for Maritime Safety
Powder Tracers
Concentrated Liquid Tracers
Sodium Fluorescein / Uranine: fluorescent tracer for hydrological tracing
Tracing in Industrial Environments
Oil and Fuel Tracers
Colorants and Markers
Fluorescent UV Markers
Powder Contrast for Industrial Filtration
Tracers for Air Conditioning and Refrigeration Systems
Contamination Simulation
Tracers for Dry Contamination Simulations
Tracers for Wet Contamination Simulations
Contamination Simulation Kit
Sodium fluorescein, also known as uranine, is a benchmark fluorescent tracer for visualizing natural flows, tracking water movement and carrying out hydrological studies with great precision. Visible under UV light and even at low concentration in daylight, it allows mapping of surface and underground water networks, measuring flow velocities or identifying hydraulic connections. At Fluotechnik, we offer sodium fluorescein solutions tailored to the needs of hydrogeologists, speleologists, consulting firms and environmental professionals seeking a reliable, environmentally friendly tracer.
Visually track the movement of water in rivers, karsts, aquifers and underground networks.
Intense fluorescence even at very low concentration, detectable in daylight or under a UV lamp.
Non‑toxic, biodegradable formulations with no lasting impact on ecosystems.
Infiltration, dispersion studies, karst tracing, permeability tests, control of natural and industrial networks.
Fluotechnik advises you on preparation, dosing and the detection equipment suited to your project.
To meet the various needs of hydrological tracing, Fluotechnik offers several formulations of sodium fluorescein. Depending on the intended application, you can choose between a concentrated powder to prepare to your own dosage, a ready‑to‑use liquid solution, or specific formulations that simplify field implementation. Each product is selected to ensure effective fluorescence, rapid dissolution and compatibility with the constraints of studies in natural environments.
Sodium fluorescein is the sodium salt of fluorescein, better known as uranine. This water-soluble dye is distinguished by its intense green fluorescence when exposed to UV light or daylight. Thanks to this property, it is widely used as a hydrological tracer to visualize and measure the path of water in natural environments (rivers, aquifers, karst systems) as well as in technical and industrial networks. Its high visibility makes it possible to detect very small amounts and to follow a flow over long distances. Used in hydrogeology, speleology, geotechnics and environmental engineering, sodium fluorescein has become an essential tool for:
By bringing together our main uranine-based solutions, this page helps you understand the differences between the available forms and select the reference best suited to your hydrological or environmental studies.
Sodium fluorescein is used as a tracer to follow the flow of water in a natural or artificial environment. Depending on the volumes of water to be traced and the objectives of the study, preparation and method may vary. Here are the general steps to follow:
Weigh or measure the required amount of dye based on the volume of water to be traced, the distance to be covered and the desired detection sensitivity. Dissolve the powder or concentrated solution in a quantity of clean water to obtain a homogeneous mixture. In hydrology, dosages often range from a few milligrams to several hundred grams depending on the scale of the tracing.
Pour the solution into the watercourse, doline, fissure or chosen injection point. Note the time and hydrological conditions. Then monitor the resurgences, springs, piezometers or sampling points likely to receive the dye. Detection can be visual (UV lamp, daylight observation) or instrumental (fluorimeter, turbidity probes).
Depending on the arrival times, measured concentrations and fluorescence intensity, determine the flow velocities, transiting volumes and existing connections between the points. This analysis makes it possible to identify recharge zones, understand how an aquifer works or check the effectiveness of a hydraulic structure. Feel free to repeat the operation under different conditions to refine your conclusions.
Choosing Fluotechnik’s sodium fluorescein solutions means benefiting from a reliable tracer and support tailored to your hydrological challenges. Our references combine performance, safety and ease of use to facilitate your investigations in the field.
our fluoresceins are selected and tested to guarantee optimal fluorescence and rapid dissolution.
all our formulations are non‑toxic, biodegradable and comply with the requirements of environmental studies.
our team guides you on the right concentration, the right detection equipment and the procedures suited to your project.
we maintain regular stock and offer fast shipping so you can intervene without delay on your sites and studies.
professionals in hydrogeology and speleology use our products daily and attest to their effectiveness.
Discover through images how sodium fluorescein is used for hydrological tracing, speleology or dispersion tests in a natural environment. These videos show the implementation of the dye, its diffusion in water and the reading of results, whether with the naked eye or through fluorescence sensors. They illustrate best practices in preparation, injection and monitoring, and show how this tracer helps to better understand the functioning of aquifers and hydraulic networks.
Discover our Hydrology & Fluorescent Tracing catalogue: a complete selection of professional solutions dedicated to tracing water flows, studying underground networks and detecting hydraulic transfers. Fluorescent dyes, fluorimeters, detection equipment and technical accessories...
Sodium fluorescein, often called uranine, is the sodium salt of fluorescein. Soluble in water, it exhibits very intense green fluorescence. This property makes it valuable for following flows or highlighting the presence of water in various environments.
In hydrology and speleology, uranine is used to trace water circulation and study the connections between different points (karst system, aquifer, resurgence). It allows transit times to be measured, flow velocities to be determined and recharge or loss zones within a catchment area to be identified.
The dosage depends on the volume of water to be traced, the distance to be covered and the detection method (visual or instrumental). Generally, a few milligrams per litre of water are used for small tests, up to several hundred grams for large river tracings. It is advisable to carry out a preliminary test or consult our recommendations to adapt the quantity to your context.
At appropriate dosages, sodium fluorescein is considered low‑toxic and biodegradable. It is used in many environmental studies without lasting impact. However, it is advisable to comply with local regulations and limit concentrations to avoid persistent coloration or visual disturbance.
Fluorescein in its acid form (fluorescein free acid) is poorly soluble in water, whereas sodium fluorescein is the salified form that dissolves easily. Uranine is therefore better suited to aquatic tracing. It should not be confused with non‑fluorescent colored tracers, such as food colorings.
In addition to sodium fluorescein, Fluotechnik already offers or will soon offer tracers based on eosin, rhodamine WT, sulforhodamine B and other specific dyes (Tinopal CBS‑X, amino‑G acid, etc.). Each tracer has its own color and characteristics, enabling multiple tests without interference or adaptation to particular conditions.
Sodium fluorescein is now indispensable for studies where visualizing water flows is essential. In hydrology, geology or environmental work, it offers a simple way to observe circulations, confirm hypotheses and quantify exchanges. The choice of formulation will mainly depend on:
Based on these criteria, you will choose a concentrated powder to dilute, a ready‑to‑use liquid solution or a specific dye. The goal remains to guarantee sufficient fluorescence to obtain reliable data while limiting impact on the environment. By bringing together our main references on this page, Fluotechnik helps you compare the possibilities, understand the advantages of each product and select the one best suited to your hydrological project.To go further, you can consult our other tracing substances (eosin, rhodamines, sulforhodamines) as well as our technical advice on dosing, the use of fluorimeters and designing an effective tracing plan. Our team is available to answer your questions and support you in your studies.
Depending on the environment being studied, the fluorescence colour required, the detection method and the type of monitoring implemented, sodium fluorescein / uranine is not always the only relevant solution. Fluotechnik helps you guide your project towards the right fluorescent tracer, the right measuring equipment or the right observation method according to your field context, your study objectives and the level of precision required.