An ITP-based system and a method are provided. ITP is used to focus a sample of interest and deliver a high concentration target to a pre-functionalized surface comprising immobilized probes, thus enabling rapid reaction at the sensor site.

Embodiments herein relate to breath analysis system. In an embodiment, a gas measurement device is included having a housing defining an interior volume. The housing can include a fluid ingress port, a fluid egress port, a bottom wall, and a circuit board disposed within the interior volume. The circuit board can include a first side and a second side, where the first side of the circuit board faces inward toward the interior volume. The circuit board can include a plurality of gas sensors disposed on the first side of the circuit board and a plurality of conductive pads disposed on the second side of the circuit board, wherein a plurality of electrical contacts contact the conductive pads when the circuit board is seated within the housing. Other embodiments are also included herein.