Rapid, on-site detection of residual explosives based on a lab-in-a-capillary and UV fiber sensor

An integrated portable system based on a lab-in-a-capillary and a UV (190-400 nm) reflected fiber sensor was demonstrated for on-site detection of trace amounts of explosives in a micro-nanoliter droplet. The filtration and measurement of the residual explosive sample were integrated in a compact device. The micro-droplet (1 nL-1 μL) was loaded onto the capillary-end by the equilibrium between gravity and negative air pressure for UV spectral analysis. Moreover, a new mixed spectrum decomposition algorithm (MSDA) was used to calculate the concentration of multiple explosives in the soil of the explosion site. This system for real-time explosive analysis features a short sample preparation and analysis time (<5 s), low sample consumption (10 nL), wide detection range (1-250 ng μL^-1), low detection limit (<10 pg), and is easy to disassemble and clean, which fulfills the requirements for on-site explosive detection.