An UltraViolet Laser-Induced Fluorescence (UV-LIF) system to detect, identify and measure the concentration of biological agents in the environment: a preliminary study

Detection and classification of biological agents are not easy, especially at an early stage of contamination and when more than one species is aerodispersed in the environment. This research aims at demonstrating the capability of UltraViolet Laser-Induced Fluorescence (UV-LIF) technique to detect, classify and measure the concentration of biological agents in aqueous samples, exploiting ubiquitous endogenous fluorophores. The incident radiation is a third harmonic Nd:YAG laser emitting at 355 nm. A spectrometer collects the fluorescence spectra that are subsequently analysed in order to achieve information about the classification and the concentration of each agent in the sample. The benefits of the UV-LIF combined with data analysis techniques concern the speed of the analysis, the limited costs for the equipment, and the possibility analyse the airflow without the need for sampling. A LIF-based system may find its applicability in different contexts (e.g. for the monitoring of HVAC systems in healthcare settings or in crowded places, such as schools or airports) allowing a fast and targeted response in the event of contamination. In this work, the experimental setup and the capability of the classification and measurement techniques will be discussed. The first measurements are shown to validate the potentialities of the LIF.