Rhodamine Dye Tracing

rhodamine dye tracing

Rhodamine is a red-colored dye that fluoresces at a particular wavelength and thus is detectable by a fluorometer when dissolved in water. It is commonly used for time of travel studies that measure the movement of water. While many studies are short-term and performed with manual sampling, other cases may call for real-time delivery of data from relatively inaccessible locations.

Rhodamine Dye Tracer Studies

The specific type of dye used in tracer studies is called rhodamine WT for “water tracer”, indicating that the dye is water soluble. It is ideal for tracer studies because it is relatively inexpensive compared to other fluorescent dyes, detectable at low concentrations, and non-harmful to humans and ecosystems.
Rhodamine sensors use an excitation wavelength of 558 nm to elicit a measurable wavelength of around 583 nm in dyed waters.
The dye will degrade over time through photolysis but remains in solution sufficiently long for studies taking many hours or days to complete.
The US Environmental Protection Agency (EPA) officially recognizes rhodamine WT as an approved dye tracer.
Rhodamine studies may be useful for tracking of pollutants, dispersion, seepage or flow in surface water, groundwater or wastewater applications.
Hydrodynamics of wetlands are commonly studied using rhodamine, particularly in relation to artificial wetlands constructed for waste treatment.
In stream hydrodynamics, rhodamine studies can help to characterize the interaction of the overlying surface water with the streambed.
rhodamine dye tracing

Typical Rhodamine Dye Tracing System

Although some rhodamine dye tracer studies can be completed in a matter of hours using handheld sampling equipment, some applications may require extended sampling over a lengthy period of time, potentially with multiple dye injections. In such cases, configuration of a telemetry-equipped monitoring station can help to deliver the project data required.

A typical system consists of an X3 environmental data logger with wireless communications mounted on a mast or other structure on the lake, river, wetland or other water body to be studied. The system can be powered with an external battery pack or SP-Series solar power pack.

Connected to the X3 is a rhodamine fluorometer for dye detection. While various sensor options exist, one of the more common arrangements is the YSI EXO3s multiparameter sonde with rhodamine WT sensor. The sonde is delivered with a central wiper to prevent measurement interference from debris and fouling. In addition, the sonde can accommodate other sensor types for measuring general water quality parameters like temperature, pH and dissolved oxygen.

Systems communicate wirelessly with the WQData LIVE web datacenter for data management and remote logger controls. In cases where more frequent measurement is desired immediately following dye injection, the intervals can easily be adjusted through the web portal. Data management is facilitated through the available WQData LIVE features for viewing, manipulating, reporting and exporting data.

For long-term monitoring at study locations, systems can be expanded with weather stations, water level sensors, velocity sensors, flow meters, and many other sensor types. The multiple sensor ports of the X3 logger allow for many instruments to be connected simultaneously.

Contact a NexSens Applications Engineer today to discuss your rhodamine dye tracing application.

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