This paper reports on a portable C sensor of trace sensitivity and yet resilient to saturation and poisoning, suitable for field use onboard unmanned ground vehicles. The sensor is based on a FAST Gas Chromatographic module (FAST-GC) and a Quartz Enhanced Photo Acoustic Spectroscopy (QEPAS) module, and can detect and identify threats rapidly and reliably even when challenged by higher concentrations of common interferents like gasoline and paint fumes.