Nilro explosives such as trinitrotoluene(TNT),cyclotrimethylene trinitramine(RDX),and pentaeryth-ritol tetranitrate(PETN)with multiple nitro groups in their structures are common ingredients of high-explosives found in many unexpected home-land security threats,mine-fields,and as commonly used industrial materials.This study aims at developing a convenient surface analysis method for quick identification of these compounds by direct analysis in real-time(DART)coupled with time-of-flight mass spectrometry(TOF-MS).