Fluorescein sodium salt powder appears as a dark orange/red powder slightly soluble in water and alcohol. It fluoresces as an intense yellow-green when mixed with water. The reaction is pH-dependent, so the color can be altered by changing the acidity of the water.
When mixing with water, a tiny amount goes a long way. This vial should be enough to dye at least 100 gallons of water. It is organic and harmless to the environment at these low concentrations.
Fluorescein was first made in 1871 and has since found a use in many niche applications thanks to its unique coloring properties and ultraviolet fluorescence.
Applications include:
- As a medical dye to diagnose blood vessels or into the eye to help detect corneal abrasions.
- In microscopy to stain biological samples in order to study cell structures and other microscopic organisms.
- To monitor water pollution in lakes, rivers, and groundwater.
- To detect and trace leaks in plumbing systems, cooling systems, and other industrial applications.
- To create glowing, colorful effects in artistic performances or installations.
- To detect blood stains at crime scenes. It reacts with the iron in hemoglobin, producing a bright fluorescent signal.
Each vial has an accompanying information card. Even though fluorescein is commonly used in medical applications, please do not consume it.