Portable fluorescence sensor for organic contaminants and cyanobacterial detection in waters

A portable sensor for fluorescence spectroscopy of liquids has been developed. This sensor exploits the autofluorescence produced by organic chemical compounds when exposed to ultraviolet or visible light. In particular, the autofluorescence produced by pigments present in cyanobacteria and microalgae allow their in vivo detection. Liquid jet waveguide approach has been chosen in order to provide efficient fluorescence light collection. A mini-spectrophotometer is used as a detector and a mini-PC manages all the instrumentation. The whole sensor is housed inside a weather-proof plastic enclosure which allows it to be transported as hand luggage. The sensor can be equipped with three different LED sources that can be easily replaced according to the needs due to the type of substances intended to detect. Several sources at different wavelengths have been taken into consideration and characterized for this purpose. The excitation at multiple wavelengths provides the possibility of discrimination between different substances or phytoplankton groups. Preliminary measurements, using excitation wavelength at 275, 405 and 590 nm, show the possibility of detecting the presence of cyanobacteria in water collected at different pickup points in an aquaponics plant.