A compact aerosol sensor and spectroscopic sorting with UV LEDs

We demonstrate a compact system incorporating a 32-element linear array of ultraviolet (UV) light-emitting diodes (LEDs) to the in-flight fluorescence detection of aerosolized particles. Custom electronics manage a standalone system and enable real-time processing of spectral data, which is used to cue a miniaturized aerodynamic deflector for physical particle separation. This front-end system improves the prospects for many second-stage analysis methods by reducing the background particle burden and providing a suspicious-particle enriched sample. The performance of UV LED arrays as an excitation source is established by the ability to detect emission from NADH and tryptophan in aerosol samples. On-the-fly fluorescence collection, operation of a real-time spectral algorithm, and aerosol concentration is demonstrated by separating particles that exhibit a specific spectral feature from a background of otherwise fluorescing particles.