Fluorometer

Modern fluorometers are capable of detecting fluorescent molecule concentrations as low as 1 part per trillion.

These two beams work in tandem to decrease the noise created from radiant power fluctuations.

Light from the fluorescence of the sample and the lower, attenuated beam are detected by separate transducers and converted to an electrical signal that is interpreted by a computer system.

The machine is constructed like this to decrease the stray light from the upper beam that may strike the detector.

This works because pathogens in milk are killed by any heat treatment which denatures alkaline phosphatase.

The voltage signal of the sensor gets converted to a concentration with a calibration curve in the lab, using either red-colored dyes like Rhodamine, standards like Fluorescein, or live phytoplankton cultures.

[8] Ocean chlorophyll fluorescence is measured on research vessels, small boats, buoys, docks, and piers all over the world.

Fluorometry measurements are used to map chlorophyll concentrations in support of ocean color remote sensing.

[9] Aquaculture operations such as fish farms us fluorometers to measure food availability for filter feeding animals like mussels[10] and to detect the onset of Harmful Algal Blooms (HABs) and/or "red tides" (not necessarily the same thing).

Filter fluorometers are often purchased or built at a lower cost but are less sensitive and have less resolution than spectrofluorometers.