Various forms of chlorophyll are bound in the living cells of photosynthetic organisms, such as phytoplankton and cyanobacteria (blue-green algae). The amount of chlorophyll found in a water sample is used as a measure of phytoplankton concentration. These measurements help to understand the general biological “health” of the system, such as its trophic state or primary production. Chlorophyll measurements can also identify algal bloom events and their impact on water quality, and predict toxic blooms.

Chlorophyll fluoresces when illuminated with light at a specific wavelength (435-470 nm). For in situ measurements, in situ fluorometers induce chlorophyll fluorescence by shining a beam of light at the appropriate wavelength into the water and then measuring the higher wavelengths of light emitted. These real-time chlorophyll measurements complement the extracted laboratory analysis.

Apure’s chlorophyll sensor is made of POM plastic and aluminum. It features a rugged gemstone lens for maximum optical performance and scratch resistance. It is a fixed response fluorometer, which means it excites chlorophyll in water at a fixed wavelength (470 nm) and then measures the subsequent fluorescence emitted (>630 nm).