The present application describes a sensor apparatus, especially an electronic nose, based on 2D films or 3D assemblies of cubic nanoparticles capped with an organic coating. The organic coating is modified with unique compositions of functional moieties, e.g. cyclodextrins, to provide the detection of volatile and non-volatile compounds derived from explosive materials, e.g. PETN, RDX, TNT etc. with very high sensitivity. The nose employs pattern recognition algorithms and methods, e.g. PCA, for detecting and quantifying specific explosive compounds.