Making fluorescent liquid, fluorescent paint or making a fluorescent object is the main application of sodium fluorescein. With a very small amount of fluorescein fluorescence can be achieved in a liquid, hence it is also commonly used in hydrological techniques.
As we have explained in this other section, the fluorescenceis the phenomenon whereby certain products or substances emit energy in the form of light when irradiated with ultraviolet light.
Fluorescence is a naturally occurring phenomenon in nature, but you can also achieve fluorescence with reagents such as sodium fluorescein. It is important to note that fluorescent light is emitted when irradiated with ultraviolet light, so it will be necessary for the fluorescent liquid experiment to also have an ultraviolet lamp or torch.
Emission in sodium fluorescein is maximal around pH 8 and with a wavelength close to 550nm. This is why, in the experiment to make fluorescent liquid with sodium fluorescein, we are looking for the water to raise the pH to 8.
Making fluorescent liquid step by step
This procedure is taken from this experiment page: Making fluorescent liquid.
- Put distilled water in a beaker
- Add a few drops of ammonia to raise the pH to 8.
- Introduce 1 gram of fluorescein sodium
- Shine a UV lamp into the glass, and you will see how you have obtained your fluorescent liquid.
This is the result in video https://www.youtube.com/embed/zsq1paqbVls?feature=oembed
Fluorescent liquid applications
The high solubility of fluorescent materials means that a very small amount of fluorescein can dilute a large amount of liquid. For example, with 20 grams of fluorescein you can dilute more than 2000L of water. This is why fluorescent materials are used for measurements in flow streams, and for their high visibility in leak detection. Here are some fluorescent tracers: https://www.alquera.com/trazadores-fluorescentes/ used for these purposes.