Air to liquid sample collection devices using microfluidic gas/liquid interfaces

We demonstrate methods for collecting gaseous and aerosolized particles into microfluidic channels. Surface tension creates gas-liquid interfaces to permit an analyte to transfer from a gaseous environment to a liquid microfluidic channel. In one device, hydrophobic/hydrophilic boundaries create a virtual channel of liquid in which analyte is collected. In the other device, pinning points create circular pillars of air within a mircofluidic channel. Multiple methods demonstrate feasibility of these devices. Nesslerpsilas Reagent (NR) with gaseous ammonia (NH₃) showed the real-time and collection-for-later-analysis acquisition abilities. Deionized (DI) water with varying concentrations of gaseous ammonia (30%, 15%, and 7.5%) showed that the devices proportionally changed impedance (~50% per step) in real-time. Aerosolized solid particles showed that these devices were also able to collect larger sample analytes.