Rhodamine Sensor

What is Rhodamine?

Rhodamine is a fluorescent tracer dye used to monitor the flow and movement of water. The most common application for a rhodamine dye test is a time of travel study, during which the time it takes for the dye to move from point A in a river to point B, is recorded.

Aquaread Rhodamine Sensor

The sensor is fixed response fluorometer, meaning it excites the dye in the water at a fixed wavelength (255nm). It then measures the subsequent emitted fluorescence (>575nm).

Key Features

Dense sapphire lenses are used on our rhodamine sensor for their high clarity and scratch resistance.
Measurement range 0 – 500µg/l.
Resolution: 0.01µg/l.
Repeatability: +/- 5% of reading.
Simple to install on a wide range of Aquaprobes.
Easy 2-point calibration using rhodamine dye.
Site specific calibration with grab sample calibration option.

Our Rhodamine sensors can be installed into many of our probes, below are some examples.

To see all of the probes that feature RHOD please visit the Products section.

AP-LITE

Single parameter Aquaprobe, for use with any of our sensors.

Aquasonde-5000

The Aquasonde-5000 has 4 spare ports. They can house any combination of ISE and Optical sensors.

AP-2000

Advanced portable multi-parameter Aquaprobe.

Simple installation

Installing the rhodamine sensor into an Aquaprobe is a very simple process. Simply unscrew the blanking plug from an appropriate aux socket, apply some silicon grease to the thread of the sensor (grease provided) and screw in the sensor. After installation full calibration is required.

Simple calibration

Part of our ethos at Aquaread is “ease of use”, so we have simplified and automated the calibration process as much as possible. The rhodamine sensor is calibrated at 2 points. A zero point and a 100µg/l rhodamine dye point. A stock solution of rhodamine dye is provided, and a small dilution of the stock is required to make the required concentration.

Once your solution is made the calibration involves placing the probe into the solution and selecting the correct calibration option from the menu. A calibration report is saved when complete.

More on rhodamine testing

One of the most common uses of a rhodamine dye test is measuring time of travel for surface, ground and waste water. Time of travel refers to the movement of waterborne substances, from one point to another in a stream during steady or gradually varied flow conditions. This form of rhodamine testing involves rhodamine being injected into the water, with the concentration of the dye is measured at other locations downstream using a fluorometer.

The fluorescent properties of rhodamine mean that when it is irradiated with a light of a particular wavelength it emits a light of a higher wavelength. The rhodamine sensor measures the light fluoresced by the rhodamine. The concentration of the dye in the water is relative to the fluorescence, so this measurement gives an accurate indication of the rhodamine levels in the water sample.

How to use a rhodamine sensor

A rhodamine sensor works by sending a light beam into the water to be tested, at a fixed wavelength. This wavelength of light excites the dye which subsequently fluoresces at a known wavelength band. The level of excitation measured is proportional to the amount of dye present in the water.

To use Aquaread’s rhodamine sensor, first install it into your probe of choice, then perform a full calibration of the using fluorescein dye. Once calibrated it’s good to go. Simply put the probe into the body of water, allow the reading to stabilise and take your measurement.

When to use a rhodamine sensor

Water rhodamine meters are the ideal solution because they can be left unattended for days or weeks. Our Aquaprobe multiparameter water testing devices are designed for use in the field, and some of the models are designed for long term deployment. Using a fluorometer in-situ eliminates the cost of lab analyses and is suitable for both continuous-flow monitoring or discrete sample analyses.

There are many applications for rhodamine testing. You can use rhodamine dye and fluorometers in surface water, wastewater and groundwater. In surface water you might study irrigation uptake by plants, spill mapping and response and mixing zone identification and characterisation. In wastewater, rhodamine testing is used to monitor sewer overflows and for hydraulic characterisation of wastewater treatment facilities for operations or environmental purposes, for example. For groundwater, you might use a rhodamine sensor to monitor aquifer hydraulics, trace pollution plumes, and tag and trace herbicide migration and dispersion.